Antilia. Vol. IV. Jq Fdez.

ANTILIA
REVISTA ESPAÑOLA DE HISTORIA DE LAS CIENCIAS DE LA NATURALEZA Y DE LA TECNOLOGÍA SPANISH JOURNAL OF HISTORY OF NATURAL SCIENCES AND TECHNOLOGY
Historia de la Biología. Facultad de Biología. Universidad Complutense de Madrid.
DL: M-34954-1995.	ISSN: 1136-2049.

FROM THE BARRILLA TO THE SOLVAY FACTORY IN TORRELAVEGA: THE MANUFACTURE OF SALTWORT IN SPAIN

Joaquín Fernández Pérez

Dep. Biología Celular
Facultad de Biología
Universidad Complutense de Madrid
28040 Madrid (España)

FROM THE BARRILLA TO THE SOLVAY FACTORY IN TORRELAVEGA: THE MANUFACTURE OF SALTWORT IN SPAIN

In the evolution of saltwort processing, three phases stand out: aeotechnique, paleotechnique and neotechnique (1). The first phase representing the very beginning , is characterised by the utilization of hydraulic energy and wood, as building materials for machinery. In the second phase, today considered archaic obsolete, energy is obtained from coal and steel is the material used for the machinery. In the third phase, electrical energy or energy from combustible fossils is used and the machinery is made of complex alloys.

This same scheme can be applied to the chemical industry in the production of saltwort . The attainment of the natural saltwort, in the form of efflorescence in salt water lakes and the direct combustion of barilla plants or aquatic marine plants in order to obtain the saltwort, belongs to aeotechnique phase. Possibly, the first process was superior to the second, and although neither hydraulic energy nor wooden machinery, there is no objection to consider these attainment processes as aeotechnique. The Leblanc industrial process, which produces saltwort from natural salt, can be compared with a paleotechnique process. Solvay method is in between the paleotechnique and the neotechnique phase. The electrolytic process for the saltwort obtention, the most modern of all of them, can be included in the neothechnique phase.

In this article will be to briefly describe the traditional saltwort attainment procedures of burning barrilleras plants. This process had great importance in Spain until the beginning of the XIX Century, long period characterised by the treatment of the native sulphate of sodium. Finally it will be seen the Solvay method was used in the first Spanish saltwort plant, established in 1908 in Torrelavega. It can be said, as regards the attainment of saltwort changed from aeotechnique phase to a very unique paleotechnique phase and changed again to another neotechnique. Nearly a century went by, between the disappearance of the first in the XIX Century and the settlement of the Solvay factory in Torrelavega and the development of the Leblanc method, in between. As will become evident later the chemical industry in Spain was very weak, and the few factories existing could not compete with the big number of them established in England, where the chemical industry was born. Spain even had to import saltwort from other countries. The closure of the industries established in Spain was determined by the low price of the saltwort imported, in relation to the one produced in Spain, during the last decades of the XIX Century. However, lot of the raw materials used in the production, either in the Leblanc method or in the Solvay, were easily got in the Spanish deposits. The causes of the lack of chemical industrialisation in Spain must be sought in the new historic queries that belong to the Spanish Economic History.

Besides the normal anhidro sodic carbonate Na2CO3 that can crystallise with 1,2,3,5,6,7,10,15 mol. of water, and between them, the hydrate Na2CO3.10H2O, the ordinary crystallised saltwort (crystals of saltwort), we know the follow combinations: Na2CO3.NaHCO3, called also natrón, trona or urao; Na2CO3. 2NaHCO3 and NaHCO3 acid carbonate or bicarbonate. All of them are included in natural saltworts.

The sodic carbonates are naturally found with other salts in some springs or springwaters such as Vichy, Karlsbad, etc. When these kinds of waters are accumulated in undrained lakes, sodic carbonate is formed by evaporation in dry zones. Overall this refers to Na2CO3, NaHCO3, 2H2O.

The oldest known saltwort deposits, are placed in the lakes of Low Egypt, in the basin of the Wady Atrum. The highly alkaline water from the 11 lakes contains carbonate, chloride and sodic sulphate. In April the level of water at its peak and they are partially dried later in summer, giving different varieties of trona. The accumulation of water from springs, which are low in salt, is so big in the summer in these lakes, that a layer of 40 or 50 cm. of sodic salts is formed, containing 30% of álkali. The deposit is a mixture of sodic carbonate and clay mud (latroni). Sodic Suphate, water and sand are also found in its composition. The deposit was extracted with the help of iron rods, used as pick and shovel. Afterdrying, it was transported along the Nile in baskets. Traditionally, it was added to the drinking water and in the manufacture of glass and soap. The mercaturum nitro, about which Plinio talked, carried pieces of "natrón", taken from these salty lakes. They were the ones that invented glass, when they used the transported "natrón" as a base to heat their cooking pots. The heat turned the mixture of silica and saltwort into glass (2).

There are also lakes of similar features in the West Coast of Aden in Arabia, in Szegedin in Hungary and in the whole steppe between the Theiss and the Danube.

Documents have not been found illustrating the desertion of the consumption of natural saltwort in the Mediterranean region and its replacement by the artificial saltwort obtained by burning the barrillera plants. However, it is possible that this corresponds with the period of the expansion of the Islam.

Natural saltwort also existed in America, called tequixquitl, tequisquilit or tequesquite. It is very probable that its pre-Hispanic use was exclusively for the seasoning of food. They started producing soap and glass with the arrival of the Spanish people. The monk Francisco Ximénez, describes it for the first time, although he confused it with nitre or saltpetre (sodium nitrate). He also says "it lathers as well as soap does". It appears on the banks of rivers and small lakes in dry season. Ximénez writes:

"The real saltpetre from the New Spain small lakes, is swept up with brooms, or it is taken in hands in big quantities when they get dry because of the summer heat. And the whitish quaxado in grains like common salt, is kept for anything that it might be needed for during the rest of the year, and it is found in abundance in every lake, mostly in this part of Mexico" (3)

This was not saltpetre but "tequesquite", that is to say, sodium carbonate. Ximénez knew and used the book of Dioscórides, translated and commented by Andrés Laguna, so that Ximénez also transmitted their mistakes. He himself, as well as Andrés Laguna, mistook the alumbre (double sulphate of potassium and hydrated aluminium) with saltwort, known by the Mexicans by "tlalxocotl", saying that it was made of "arab Kali herb". These mistakes might come from the confusing comments of Laguna. Actually, Laguna wrote literally to Dioscórides "Preparing the "alumbre" called Catino, from the ashes of a salty herb called kali in arabic, glass is often made" (4).

Similar mistakes were made in other descriptions, over all referring to its composition. For instance, the Italian adventurer and traveller Giovanni Francesco Gemelli Carreri wrote down this confusing paragraph about his travel to New Spain in 1697:

"I arrived by canoe to the small village of Iztacalco, which in Mexican language means white house. By boling lake-water with soil called "tequisquite" or saltpetre, and draining it away by a tube, salt is made" (5)

Another mistake in this comment is that "iztacalco" in nahuatl means "house of salt", whereas "iztaccalco" means "white house".

Antonio de Ulloa, who saw it in the small lakes of Mexico, also considered it to be saltpetre. The great sailor and scientist speaks of its use either as seasoning, due to its part of common salt, or as dye fixer (6).

In the XVIII Century, Francisco de Ajofín calls the "tequesquite" "land's salt", saying that it was used together with the lime to produce the bleach needed in making soap (7).
.
The metallurgist José Garcés y Eguía is right in saying that the "tequesquite" is "a native mineral alkali" (carbonate of sodium), and he used it in a process of melting down silver-ores (8).

References to "tequesquite" are frequent in Natural History papers, at the end of the XVIII Century and beginning of the XIX. Miguel del Barco, for instance, in his work about California, writes:

"In moist places, instead of saltprete they have "tequesquite", the Mexican name given to a sort of saltprete in New Spain. This does not whiten the soil, but keeps its natural colour, softens the surface, and it is said that it looks like the lather of the soil. The "tequesquite" easily softens the beans by putting a little bit into boiling water. It also facilitates the washing of clothes, preparing it in water of "tequesquite", and of course, it is one of the ingredients needed for making soap, for which saltpetre is said not to work" (9)

The famous chemist Boussingault described saltwort deposits in Lagunilla (Colombia), but we have not found any other references to this, before the independence of the republic.

III. THE OBTENTION OF THE SALTWORT FROM BARRILLERA PLANTS

After the disappearance of the "natron" trades in the Mediterranean, as has been mentioned before, it was replaced by the combustion of some kinds of plants. Then it was named Álkali fijo mineral. It was sodic carbonate, although this was not the only component. In Spain started being called soda, sosa and barrilla (10). Nowadays few people know that the majority of the saltwort used was got burning certain number of plants until the first decades of the XIX Century, in the Mediterranean coasts, maybe since the Arabic domination. The regions of the Eastern Spanish Coast and some inland areas will produce a much-valued barrilla, especially the Alicante saltwort.

The "barrillera" plants live in saltern, salt marshes, salines or coastal salt marshes. The soil of these formations, rich in soluble salts of sodium or magnesium, causes changes in the vegetation that usually do not go unnoticed to any observer. The salines can be coastal or interior. The latter are placed in resevoir where accumulated rainwater or springwater, which is highly conductive, dissolve the soil salts. This kind of soil is too restrictive, and the plants that grow there, are physiologicly adapted to these contingencies. In some cases, the salines species have survived with foliate glands that quickly excrete the salts. In other cases, plants have developed a water accumulation system in their leaves to avoid a fall in osmotic potential caused by the increase of saline concentration. These two biological resources are mechanisms that provoke the high salt concentration in the "barrilleras" plants. When they are burned, they produce an important quantity of sodic carbonate.

The coastal inlets, saltern and salt marshes have a similar floristic composition to the interior salt marshes. This is the reason why it is supposed that the latter have been colonised by the seeds of the former. Plants with fleshly leaves and stems constitute the salt marshes perennial vegetation. The salt marshes species are quite vulnerable to soil changes and for that reason, the colonisation is very slow. Those changes are caused by the irregularities in the phreatic level. It gives rise to the increase or decrease of soil humidity, and therefore its salinity.

These salt marshes, which are the most important example of the adaptation of vegetables to salinity, constitute a specific regressive ecosystem, deeply threatened by the antropogenic manipulation of the phreatic levels. The current value of the salines for the study of halophit plants and the fauna surrounding is not comparable to the value they had when they were used as a source of saltwort in the XIX Century.

Since then, the "barrillera" plants were collected or grown with the aim of obtaining saltwort, manufacturing glass and soap, and to whiten and fix dyes in the textile industry. This important industry disappeared completely around 200 years ago. No "barrillero" artisans are left and their simple tools disappeared. Very few written or drawn documents remain (11).

The fine barilla profited better yields of saltwort than the rest of the plants. This plant scientifically called Halogetum sativus and before Salsola sativa, was scientifically described by a Linné Pehr Löfling´s pupil during his stay in Spain in the middle of the XVIII Century (12). Antoine de Jussieu showed it to the European scientists in 1717 (13). Jussieu published a picture in order to make it known. Saltwort was known but not the plant. Their most suitable habitats, as La Gasca said, are Molinet and San Julián hills near Alicante (14).

Although this specie is the most valued, other were grown with the same aim belonging to the genus Salsola, Salicornia, Suaeda, Atriplex, Sarcocornia and others. Other plants used to produce saltwort or adulterate it, were the scattered plantain, the Zostera and some seaweed from the genus Sargassum and Fucus. An African coastal plant known as escarchada was brought to the Canary Islands, which was burnt with algazul or aguazul (Messembryantmum spp.) (15).

Soap beads were used in America instead of soap also called Santa Helena's Beads, as Nicolas Monardes writes:

"A box made of cork was sent to me, filled with round and very shinny round and black beads, as made of ebony. They grew on a small tree, were bent rather than straight, like a holm oak, and its leave looked like those of a fern. Its fruit is nut-sized, covered by a sticky outgrowth which when taken off, shows a very round black and hard bead.

This fruit is used instead of soap. So that, two or three of them in hot water to wash clothes, have the same effect that a pound of soap. In this way it foams and it has all the same effects as soap and in this way the soap is gradually wasted away until only the beads remain under which this fruit can be found and which pretty rosaries can be made that look exactly like ebony" (16)

Monardes, who never was in America, is very explicit in his explanation. Surely he talked about the usually known "xaboncillo" (Sapindus saponaria). The botanist Hipólito Ruiz describes it as "a leafy tree, of six to eight poles, of which fruit called Bolillos and Choloques, have a soapy peel that is used by poor people to wash their clothes" (17). Another specie from the same family, called Arbol de Cuentas de Rosario (Llagunoa nitida) was also used with the same propose in Chile (18). Despite in Spain were eventually used soapywort herbs (Saponaria officinalis, and Samolus Valerandi), which lather with water, the features of the soapywort beads compared it to the soap from this epoch. Three beads were equivalent to half pound of soap (230 gr.), which was very significant.

Besides the American soapwort herbs, in some areas of the Peru viceroyalty were burnt lot of plants that were similar to the "barrilleras".

"A lot of saltwort or "barrilla", called "lico" were cultivated, of which they made bleach, and they get much tallow from goats bought in the region of Piura" (19)

Despite the confusing comment, where lico rather than litho is used (20), the note is interesting because it shows that the lack of saltwort in some regions of the Peru Viceroyalty, caused people to obtain it by burning plants. To accept the word "litho" is preferable, so that the botanist Hipólito Ruiz uses it. On the contrary, he does not explain whether the name given to the plant is also the product name. Anyway, "litho" is a plant from the Aizoaceas family, Sesuvium portulacastrum. His plant was burnt near Ica in the Peru Viceroyalty. It is also possible that the barilla was grown close to the Concepción. In this respect, Hipólito Ruiz says: "it is said that the barilla or Saltwort is farmed on the Coast [La Concepción], but I have not seen it" (21). In Piura and Mendoza the industry of the soapwort vat was remarkable (22).

In New Spain were also burnt some plants to obtain saltwort and the culture of Salsola soda was introduced. Humbolt, talking about the "Casa del Apartado" of Mexico, where glass was produced, nitric acid and gold and silver were taken apart. He says:

"The glass is composed of 0,46 of quartz, extracted from Tlalpujhua streaks, and 0,54 of saltwort. Xaltocan and Peñol Indians got it from the incineration of several substancies such as: Sesuvium portulacastrum, new species of Chenopodium, Atriplex and Gratiola, (described in the Mexican Flora by the notable Sessé and Cervantes), and Salsola soda (coming from Europe but cultivated in the Valley of Mexico). The last one could be eaten as legume or reduced to ashes. This Xaltocan saltwort has a mixture of potash sulphate and lime. The carbonate of saltwort [tequesquite], found in the efflorescence of almost every clay land, would be more suitable to produce glass" (23).

I have not been able to find a description of the process followed to burn these plants in America, but it is probable that, because of its Spanish origin, the process was the same used in the metropolis.

In Spain the culture of the "barrilla" not only did expand along the Eastern Coast but it was extended over Granada, Sevilla, Aragón and a big part of La Mancha, in the middle of the XVIII Century. The flowers were collected in September, when the plant fructified. The calyx and bracts were taken out of the flower when it was dried. The flower was strongly knocked down in order to get the seed out. These seeds were planted in the Coastal between October and January, and in the inland between March and April. Once the flower was mashed, the little sticks were separated from the rest of the flower and bracts. Then, seed was scattered all over the land, in days of strong wind. After doing this a plank was passed to bury it (24). In good conditions, the seed germinated after 48 hours. Sometimes the land was sort out to remove weeds. When it grew together with cereal, two things could happen: the cereal was removed if it was drought, and it was kept if it rained. In other occasions it was planted with poppies, anise or cumin.

Between July and August the plant was ripe, that is to say flourished and with bulky buds. Then, the plant still with the root was pulled up and put in piles of one metre and a half of height and two metres of base, called garberones. Plants were spaced out to get them aired and well-dried, process that would finish in two weeks. The pile was much larger (known as garbera) if it was going to be burnt. The pile was covered with hay, straw or bulrush and it could be kept for one or two years.

After being dried, the "barrilla" plants were burnt. We have only descriptions about this process. We have used Mariano La Gasca's one and others of the same period (25).

People in charge of melting the plants were called burners or maestros barrilleros. They came from eastern regions and travelled where they were required. They used to travel through the Valencia and Murcia kingdoms, but sometimes they went up to Sevilla. Their skills in this elaboration could not be ignored, because the details that had to be taken into account were not easily learnt. This technique was full of empiricism: the amount of fire was essential since the result could be a good stone of saltwort or simple ashes without value. The "maestros barrilleros" had one assistant and four or five unskilled labourers, all of them as employers.

Burning the "barrilla" was a very laborious work that lasted 28 to 40 hours. They had to be very attentive to keep the adequate fire and poke the embers. The herbs had to be well dried, neither moist nor green; otherwise the stock obtained from the melt would not be thick enough. The combustion should be accomplished in a windy day, as if it was too slow or the flame was very small, the stems did not melt and they would become coal. If it happened there was an important decrease of the metal and the stone lost part of its value. The slow combustion also increased the day's wages, therefore the master and the assistant took 6 hours turns to take care of the process.

Combustion was made in holes dug in the same land where the plants had been sown. Land had to be very compact to avoid the landslide of the walls of the hole when the mass was being manipulated. If land was not suitable, the walls and the bottom of the hole were covered with clay land. A round ditch was broken in the ground. It had the same diameter as the hole. Then, the clay land was poured off and rolled inside the ditch and later the mould was taken off. The hole had a pot form. The diameter of the base was 4 to 7 feet (around 1 or 2 metres), the lip was more narrow and stick out 10 centimetres. The hole was 3 or 4 span of depth (0, 69 to 0,93 metres). This size depended on the size of the stone the "maestro barrillero" wanted to get. The stones weighed 20, 30, 40 and up to 50 quintals (1 quintal are 46,009 Kg). La Gasca pointed out that a stone of 30 quintals required a lip hole of 3 span and 2 fingers (73,625 cm) and a belly of 5 span and 4 fingers (32,98 cm). The morphology of the hole helped to keep in the heat needed for the melt of the herbs.

To produce 1 quintal of stone were needed 4 quintal of dried herb. When the "barrilla" was sown in the best land, 3 and a half quintals were enough. The number of holes depending on the amount of herb that had to be burnt.

The hole was burnt before starting burning the herbs. Then the ashes were retired and the hole was filled of herb, which had to stick out of the kiln. A quicker, complete and homogeneous combustion was got making two hollows in the herb: one from where the air blew and another one in the opposite side. The most skilful "maestros barrilleros" moved the pile of herb with a sickle to avoid it making soggy. Others burnt the herbs on green poles or iron rods. These were put on the lip of the hole to avoid the herbs falling without burning. The most important thing was keeping the combustion on the top, so that the melt product would fall into the hole. If it rained, the herb of the centre of the "garberones" would be the one used.

The last step after burning was called choca in Valencia. This one consisted of poking the melt mass inside the hole and later crushed it. When there was around four fingers of barilla's stock at the bottom, it started poking and crushing. The aim was to mix the melting mass, giving off the air or the bubbles and giving it uniformity when the mass got to be frozen. The homogeneity of the stone was very valued in the market. The crushing was done three times during the combustion. The first one, when half of the "barrilla" was burnt; the second, when three-quarters were burnt and the third one when the herb was completely burnt. The poking was done with sticks (called hurgones), which looked like a plough of beam, although thinner and lighter. Sticks had a point end covered by an iron plate. Another instrument, used to crush was the chueca. It was a bent log, thicker in its end with plough's beam shape. It used to be 7 or 8 feet long (more than 2 metres), and it was made of pinewood. The end with the melting mass was crushed, was also protected by an iron plate to avoid being damaged or burnt. Sometimes the "hurgones" and "chueca" rested on crosspiece joined to two straight bases over the hole. The two instruments could be moved in the interior of the hole and the worker did not hold it up in the air. Other burners did not rest the "hurgones" and "chuecas".

The poking process consisted of shaking the mass with the four or five "hurgones" that were into the hole. This started from the edges of the hole, and the "hurgones" were moved at the same time and without touching the centre, where the herb did not burn yet. When the mass of the edges had been well poked the "hurgones" were driven into the centre. Without separating the points, they stirred softly the centre, which was called "pie" when it was well burnt and melted. Once the poking was finished, it started using the "chuecas". First of all they progressively crushed the mass of the edges towards the centre. This action finished when the mass was uniform and did not have bubbles. After the second and third burnt, they started poking and crushing. Last crushing was the most laborious because of the size and the viscous state of the mass.

Once finished the whole process, it was used to pour two pitchers of water to facilitate the freezing before covering it with ground. Other burners covered the mass obtained straight with ground. The mass was set after 48 hours. This time passed the stone could be take out of the hole. Usually they were kept inside during one or two weeks, although its extraction could take longer than 1 or 2 years. If the combustion had been deficient and the mixture was not good, ashes and dust were obtained. This was called zorro.

The obtained stone had the shape of the hole, of half yard of thickness (0,42 metres). La Gasca described it:

"It is solid, in light bluish grey, turning into white, which fragments sounded as metal; full of small holes in the surface and a very fine grain in the interior; dried touching, without disgusting smell, salty alkaline taste; wet it had smell of urine" (26).

A deeper ditch was broken beside the hole to take out the stone. It was divided in three, four or five (each weighed between 200 and 300 kg) with a large hammer. Those which weighed less than 5 pounds (2,3 Kg), were not carried to the market because in contact with air they reduced to dust. Harvester kept and added them to the next combustion together with the remains of ashes, leaves and small branches leftover of the "garberones".

The "barrilla" obtained, besides sodium carbonate, usually had sand, saltpetre and ashes from other plants that were not fine "barrilla". The presence of these products was unavoidable although they were considered as a fraudulent mixture when the addition was made on purpose (27).

The data about the production and exportation of the "barrilla" in Spain was not very known. La Gasca was exaggerating when he said that fine barrilla in Spain had produced more millions than the Potosí and Guanajuato mines (28). This statement wanted to point out the slight scientific importance given to the "barrillas" plants despite their great economic repercussion. He also wanted to draw the attention to the decline of this sort of the production after the Independence war and the risk of being replaced by the artificial saltwort from common salt.

The botanist Cavanilles said that the annual production in the kingdom of Valencia at the end of the XVIII Century was about 332.700 @ arrobas (around 3.827 tones) (29). It was in Alicante, Pinós, Dolores and Crevillente where the "barrilla" was mainly produced.

La Gasca established the export trade in 581.708 annual arrobas (around 6.691 tones) for the quinquennium of 1802 to 1806, based on the data provided by the Head of the Department of the "Balanza de Fomento". These figures referred to the Commercial Ports of Cataluña, Alicante, Cartagena, Málaga and Sevilla (except Cádiz and Aguilas). La Gasca also showed that exports of similar products plus the smuggled goods would increase this amount three times. This means that 20.000 tones could be exported, of which 5.750 tones were exported to England (30). Payen estimated the value of the amount of barilla sent out to France, in 20 millions of reales. The 888.888 arrobas exported, paid to 22.5 reales per arroba, entailed around 10.224 tones (31).

In 1815, surely caused by the war, only 27.932 arrobas were sent out and the price had dropped to 40 reales per quintal (32). In 1834 the exports were recovered and the figures reached were similar to the XVIII Century. Through the Port of Alicante 338.160 arrobas sent out (3.889 tones) (33). In 1843 79.416 arrobas were exported and the amount in 1844 was around 84.388 arrobas (34). The final drop took place from the sixties of the XIX Century. In 1862, exports through the Port of Alicante measured 4.864 arrobas; in 1865 were 2.732 and in 1870 only 376 arrobas (35). This was the end of a Spanish traditional industry that could not bear the competition caused by the prices of saltwort obtained by other procedures. In fact, in 1845 the production of sodium sulphate measured 2.350 quintals (9.400 arrobas) in Cerezo del Río Tirón, and from another deposit near Cervera were extracted 5.000 quintals (20.000 arrobas) in 1844 (36). Gradually the saltwort production changed its course. We do not know much about the yield of the "barrillera" plants culture, and that is why we cannot explain the real cause of the culture of plants and barilla's production decadence (37). The "barrilla" was very appreciated among the manufacturers of glass, which was used to produce precision instruments (38).

IV. THE SALTWORT PRODUCTION IN SPAIN DURING THE XIX CENTURY

Besides the traditional procedures that lasted a big part of the XIX Century, deposits of sodium sulphate were exploited in some Spanish counties. The saltwort that was not obtained by the process of burning the "barrilleras" plants was called artificial barrilla. The Leblanc method was already known in Spain, as appeared in an article in the magazine "Revista Minera" N.299 (1 November 1862) Volume XIII.(1862) This article reported the saltwort production in South Lancashire. José Canalejas y Casas made also references to the procedure and the 50 English factories, in a comment referred to the production of the chemical industry presented in the London Universal Exhibition in 1862 (39). The engineer Rafael de Amar de la Torre makes an eloquent description:

"The process of manufacturing the "barrilla" starts anywhere with the preparation of the sodium sulphate from common salt and sulphuric acid. Then this sulphate is extracted from the artificial barilla. Spain as a special privilege, has mines of sulphate such as the Tajo, Tajuña and Jarama basins. It was generally believed that with the discovery of these mines, the saltwort industry would take a great relevance in our country, since nature had already produced the principal product, the sulphate. In the rest of Europe, the preparation of this substance, is the most expensive operation in the manufacturing of the barilla. Several factories were established near Ciempozuelos, Aranjuez and other villages nearby. It was planned to export part of the production of sulphate for the manufacturing of glass. The rest would be used for the preparation of the barrilla" (40)

Some years before, it had been thought that the solution was to use the "glauberita" (sodium sulphate), which was easily found in some fluvial basins near Madrid. In this way, the press reported the inauguration of a sodium sulphate crystallisation factory in Ciempozuelos, and the visit to another one of sodium carbonate production:

"Few days ago the inauguration of a crystallisation factory took place. This factory was built by "El Amparo" society in its rich mines of sodium sulphate, near to the Ciempozuelos railway station. The great discovery of the seam of this mineral, made that many people attend to the official inauguration of the factory, besides the Directive Board of the Society. The retinue met in Ciempozuelos, crossed the river Jarama...immediately after the dissolution works were inaugurated. A great steam boiler started working. It cause fascination the perfect order of the vats and crystallizers which have transformed the before isolated Jarama banks...Coming back...was visited the factory established for the elaboration of the "barrilla" and carbonates in Valdemoro, complement of the system in this sort of production. The retinue went through the vast building and it could admire the solid construction of a very high chimney for the furnaces, as well as examine the big amount of "barrilla" piled in its warehouse.

One factory was placed beside a hill laden with this mineral, the other established in the middle of the road that crosses the village, and both of them near to the Mediterranean railway. With these factories, our industry counts on a powerful element, so that it will not have to import this item, which applications in the trade are known as well as appreciated" (41)

It is inferred from this article that nearby the deposit, the sodium sulphate was only purified and crystallised. Afterwards, it proceeded with its calcination together with coal and chalk, in Valdemoro.

Despite the good prospects, the reaction between the chloride of sodium and the expensive sulphuric acid was not taken into account, first phase of the Leblanc method. First of all, the sodium sulphate was not pure but mixed with calcium sulphate. To obtain it purer had to be dissolved, lighten bleaches and crystallise and dry the sulphate. This last operation required quite combustible, what reduced the benefits. After drying the sulphate had to continue the process, melting in reverberatory furnaces the sulphate with coal and calcium carbonate. The lower was the melting point of the coal, the better was for the process and the calcium carbonate used was chalk, ground and dry. The Leblanc original mixture was formed by 100 parts of sodium sulphate, 100 of limestone and 50 of coal. We ignore the details of the process and the type of furnace used in Spain. It is very probable that little furnaces of manual work were used in the calcination. These were not of great size, however the one recommended by Leblanc had a 2x1,5 metres of floor. Later, they became bigger.

The elliptic reverberatory furnace used in the Leblanc factories, had the elliptic floor divided in two spaces (double couvette). In one of them, the common salt reacted with sulphuric acid to produce sodium sulphate. The hydrochloride acid could be taken out or taken in receivers of water. The second division of the furnace was used to process the mixture constituted by sodium sulphate, calcium carbonate and coal. The sodium sulphate was very divided, chalk was added in powder and coal was pulverised in one sixth whereas the rest were fragments. The second phase took from 6 to 8 hours. The next description can illustrate the process:

"With the furnace well warm, the mixture is poured and the worker extended it with an iron spit, so that it forms a homogeneous layer covering the floor. One hour later, it is turned from the right to the left and the other way around, during similar intervals of time. Mass is moved with iron scrapers, producing a multitude of little blue (combustion of the oxide of carbone). When the mass is in liquid state is dragged up to the lip of the furnace; finally, it is poured into cubic iron moulds" (42).

In some other texts, instead of the word "espetón"(spit), appears "hurgón". Probably, these words are related because the old "maestros barrilleros" or burners were in touch with the first workers of the furnaces. Although it was unlikely that the "maestros barrilleros" carried out this work in the reverberatory furnaces of the new saltwort factories, their work in the holes burning the "barrilla" was very similar.

The product obtained called black ashes, constituted by sodium carbonate (more than 40 %) and other compounds could be sent to the soapwoker and glassworker. In other cases, due to the lixiviation was obtained a soluble part that contained sodium carbonate and caustic saltwort, and another part containing the impurities high in calcium sulphide and calcium carbonate. The first of them provoked, in contact with rainwater, the formation of sulphurette that made the air unbreathable nearby the saltwort factories, which used the Leblanc method.

The result was a sodium carbonate very expensive that soon could not compete with the foreign saltwort. In fact, the British saltwort, which production in 1860 was around one million of tones, started being competitive against the Spanish satlwort produced from sulphate of saltwort in the 60´s decade of the XIX Century:

"The mines of saltwort sulphate are damaged by a strong competition of new products that the foreign industry, England principally, has introduced in the market to replace the natural and artificial barillas" (43).

Contrary to what it was expected, the sulphate exploitation did not reach very good results, in spite of having gone through the half of the Leblanc procedure.

The deposits were in the counties of Burgos (Cerezo del Río Tirón), Logroño (Alcanadre), Zaragoza (Mediano), Valladolid, Madrid (Ciempozuelo and the Jarama, Tajo, Tajuña basins) and Guadalajara (Tajo and Tajuña basins). Vilanova indicates the "thenardita" (saltwort anhydrous sulphate), in a chapter about soluble sulphates. Rafael de Rodas discovered this in the saltern of Espartina in Aranjuez. This mineral was analysed by the chemist José Luis Casaseca and he dedicated it to his professor, the French chemist Thenard. It appears in Aranjuez with crust shape, and it was called compact mineral. This mineral was used as a purgative, for the obtention of sodium carbonate and to produce glass. Another sulphate indicated is the "exantalosa" or "Glauber salt" (hydrate sodium sulphate). It was found in deposits of Cerezo del Río Tirón (Burgos), Andosilla (Navarra), Alcanadre (La Rioja), Cabezón de la Sal (Santander), Calatayud (Zaragoza) and in Aranjuez, Chinchón, Ciempozuelos and Colmenar de Oreja (Madrid).

Their uses were the same as the "thenardita". Finally, he mentioned the "glauberita" (sodium and calcium sulphate), found in Villarrubia de Santiago (Toledo) and Ciempozuelos y Chinchón (Madrid). Their uses were also the same as the minerals mentioned before (44).

In 1865, they were only exploited in the county of Madrid some deposits of the left bank of the Jarama, within the municipalities of Chinchón, Ciempozuelos and San Martín de la Vega and also in the Tajo´s right bank in Colmenar de Oreja. The use of the mineral was carried out in Ciempozuelos, whereas in Aranjuez and Valdemoro it was proceeded to the attainment of the sodium carbonate. In Aranjuez, where there was a factory that produced hollow crystal, at that time an enterprise made some technique improvements:

"The French Society called " Compañía de minas de sosa de Aranjuez" is making efforts to improve the "barrilla" production and it has increased the number of some instruments in its office, with the aim to manufacture caustic sodium in order to compete against the British. This seemed to be very unlikely, due to the expensive price of combustible in this county, besides the difficulty of transport to cut short the distance between the factory and the railway station and others reasons explained before" (45)

The exploitation of these deposits was very traditional: "arms in excess and consumption of wood", there were no steam machines, the mounted transport was used to go from the deposits to the factory and from here to the loading stations. Here it is a description of the operations of the sulphate exploitation in the factories of Cerezo del Río Tirón, (possibly very similar in any other places), which illustrates the precariousness of technique means, if compared to the prosperous British saltwort factories at that time:

"The process of exploitation is a clearing along a steep formed in the left bank of the river Río Tirón. The mineral is found in alternating stratum with marl and gypsum from the tertiary age. They are two varieties recognised in the region: the charro and the canto. The former is easily soluble in the water, and the second needs to suffer a long exposing to the atmospheric conditions, which facilitates its dissolution, forming efflorescence in the surfaces that gradually penetrates in the interior. Both varieties suffer a dissolution in hot water after the fragments had been reduced by crushing to a nut size. In the "Singular Española" lead the hot water from the boiler to the zarzos (tissue of poles, cane or wicker forming a flat figure) made of wicker over that is placed the mineral. Workers stir this mineral with wood shovels to facilitate its dissolution. It is led from wood pipes to a vat, where the earth parts are stored, and it is obtained the sufficient degree of saturation to go to the crystallisers. These are in regular compartments dug into the ground, and protected by a shelter. Under each shelter there are many crystallisers, of low depth. The water from the vats is distributed in the crystallisers through their corresponding pipes. The pure and crystallised sulphate is obtained in these compartments. But before being commercialised, it has to lose the humidity and water of crystallisation. Referring to humidity, the sulphate is put on iron sheets and a flame is passed below them. The loss of water, is reached in the reverberatory furnace of flat floor" (46).

This process was done, in small scale, in threshing floor through natural evaporation. In another factory placed in the same village, water charged of sodium sulphate coming from different sources. Later they were led to an artificial evaporation in ironed boilers from where they passed to the threshing floor to be crystallised (47).

In 1846 the furnaces to obtained the carbonate had already been built in an establishment in Cerezo, although they were not working yet (48). José Grande thought hopefully that it would avoid depending on the French saltwort importation (49).

The mineral was transported from the deposit to the factory in mounted transport. At that time, there were four mines property of the "Cerezana" and "La Constancia" Companies. Either transformed in "soil" or "stone", the mineral was carried to Briviesca or Pancorbo railway stations that were equidistant. The sodium sulphate was sold for 43,50 to 54,25 reales per quintal in the station. The buyers sent it to the factories of La Coruña, Avilés and other places. Glassmen themselves, transformed the sulphate in sodium carbonate to be manufactured. This artesian industry would never be as the authentic chemistry industry extended through England, France and Germany.

Despite the technical backwardness and the doubtful profitability of the saltwort mines, new deposits were exploited, such as in the municipality of Villarrubia de Santiago in Toledo.

The major disadvantage was the coal's price, according to the Spanish experts of that epoch. Coal was 30 "escudos" more expensive in Spain than in England. Taking into account that, to obtain a tone of sodium carbonate it was needed 2,25 of coal, the difference of price was 67 "escudos". Coal high prices in Spain were caused by the high tariff of the railway transport. Some calculations made by Amar de la Torre, showed that the tone of "artificial barrilla" (saltwort) in Madrid, was a 30% more expensive, if this was Spanish rather than English. With a drop in coal prices to the half, the Spanish saltwort could have been able to compete with the British. In this way some solutions were considered to get a drop in combustible price: to eliminate the import rights, reduced costs in its railway transportation and the hope that the North railway provided abundant coal of quality and low cost.

The consumption of saltwort in Spain was not very important at that time. This is the reason why the import was limited to 6.653 quintals (1 quintal equals 46,009 Kg) in 1862, 5.885 in 1863 and 10.999 in 1864 (50), whereas the sulphate production was of 50.217 quintals in 1862, of 80.899 in 1863 and of 118.217 in 1864 (51). It would be very difficult to calculate the percentage of the product imported because it was surely carbonate and the statistics of production were referred to sodium sulphate, obtained a foot of the deposits. The Spanish sodium sulphate deposits stopped being exploited as the sodium carbonate factories closed, because of the foreigner competition. In the 1893 statistics was only indicated the exploitation of the Cerezo del Río Tirón deposits. The production of that year was calculated in 100 tones, that valued 750 pesetas a foot of mine.

The foreign saltwort import, which was much cheaper than the one produced in Spain, meant the death of the incipient Spanish chemical industry. The big hope of the beginning became later a great disappointment. It was the high cost of the combustible and coals what put end to production. Although is also possible that the lack of good chemists and technicians was another factor to take into account.

V. THE SALTWORT PRODUCTION BY THE LEBLANC METHOD

As indicated above, the situation in Spain until the last decades of the XIX Century was to obtain sodium carbonate from sodium sulphate. The latter was obtained by exploiting some deposits. Leblanc, who will be discussed later, developed the second phase of the procedure.

Nicolas Leblanc (1742-1806) formulated the industrial process for the attainment of saltwort procedure, which carries his name in 1789. The reasons that led to the development of this procedure are useful in understanding the close relation between science and society. Moreover, this procedure is closely connected to the birth of the great chemical industry.

Around the middle of the XVIII Century the production of natural saltwort and salwort obtained by plants, could not cover the increasing demand for the fabrication of soap and glass. The incipient textile industry and the personal hygiene together with the comforts daily life demanded both products. In many cases the saltwort was successfully substituted with potash, at that time a cheaper component of producing soap. Soft potassic soaps could be converted by means of common salt into sodium soaps.

Henry Louis Duhamel was the first to recognise the difference between sodium and potassium salts. In 1781 Keir de Tipton obtained saltwort from sea salt to meet his needs for soap production (52).

In 1776, the Academie Des Sciences of Paris offered a prize of 2.400 pounds to the best method that provide for the attainment of saltwort from common salt. The prize was never given, on the one hand because the proposed method were not usable and on the other hand because of the revolutionary environment of the time. The first contender, Malherbe, established the conversion of common salt into Glauber salt, using sulphuric acid. The Glauber salt, by means of calcination of wood coal should yield saltwort. De la Métherie tried, with his method to convert Glauber salt into saltwort directly by calcinating coal. This reaction gives off sulphur bioxide. As this process ielded very little saltwort the second contender recommended decomposing the products of the reaction, principally sodium sulphur, with acetic acid and converting the acetate by means of calcination into saltwort (53).

These inapplicable procedures led Leblanc, around 1787, propose the reduction of Glauber salt with the addition of lime. In order to develop it, he counted of the help of a well-known chemist called Dizé (54). In these way a practical and usable method for the attainment of artificial saltwort was born ; but the political changes harmed the development of the artificial saltwort industry in France. Leblanc, with the helpof the Duque d´Orleans set up a factory in St. Denis in the region called at the time Franciade. This factory succeeded in producing 250 to 300 Kg. of saltwort daily. After the execution of Philipe-Egalité, in 1783, the factory was confiscated and closed. Nicolas Leblanc, after the revolutionary period, unsuccesfully tried to claim his lights over the factory but his claims were not heard. Desperate, he committed suicide in 1806. His method of saltwort attainment was the basis of the great chemical industry of hte XIX Century. The fabrication of sulphuric acid and of nitric acid was developed when this method was ready. These compounds were necessary in the saltwort elaboration process. A by-product of hydrochloric acid, the base of the chlorine industry in the form of calcium chloride is the bleaching agent that conquered the textile industry.

J. Muspratt perfected the Leblanc method introduced in England in 1794, and big factories were built from 1823 on (55). The English domination of the saltwort production would last several decades. In Germany Hermann in Schönebeck set up the first factory in 1840.

The attainment procedure consists of melting a mixture of sodium sulphate, calcium carbonate and coal in open-flamed furnaces. The proportions of those components prescribed by Leblanc were one part sulphate, one part lime and half part coal. The reaction, in two phases, is as follows:

When the principal reaction tales place, there is an increase in temperature; the coal reacts with the calcium carbonate according to the following reaction:

The flames produced by the production of oxide of carbon called candles in England and lamparillas azuladas in Spain, turn yellow in colour by reacting with the sodium and indicate to the workers that the reaction was finished; they should therefore take mass from the furnace. If the mass were not taken out of the furnace at that time, the saltwort and calcium sulphate would react as follows:

Then red or burnt masses what are difficult to leach and which yield very little saltwort resultated. This frequently happened in manually manipulated furnaces; but it appears that mechanical furnaces regulated the temperature better and the process was developed more successfully. The substances needed were sodium sulphate, formerly known as Glauber Salt, limestone, and coal. In order to prepare the Glauber Salt it was necessary to treat the sea salt with sulphuric acid (2NaCl + H2SO4 = SO4 H2 + 2HCl). It was the most difficult part of the production process, since large amounts were necessary and its transport was difficult and expensive.

As has just been demonstrated, large amount of raw materials was needed for the attainment of saltwort: coal, common salt, limestone and sulphur. In England's case, which developed an important chemical industry for the attainment of saltwort by means of the Leblanc procedure, production depended on the importation of sulphur (56).

In the mid-XIX Century, the most important known source of sulphur were in various places (Radoby in Croatia, Szwoswice, South of Cracovia, Czarkow, Milo Island, Murcia, near Apt in Vaucluse and in the Red Sea), but in Sicily was the most commercial salt relevant in the beginning of this type of chemical industry. In 1820, the saltwort attainment industry consumed 5.000 tones and in 1838, it reaches 45.000. Between 1834 and 1823, the Tennant factories from Glasgow and Muspratt of Lancashire bought Sicilian mines. Due to the Sicilian sulphur monopoly and subsequent increase in cost the attainment of sulphuric began to be acquire from pyrite, firstly from the Wiclow mountainous and later from the richest mines in Huelva. In 1862,90% of sulphuric used in the saltwort chemical industry came from the treatment of pyrite, 50% of which originated from the mines of Rio Tinto in Huelva (57). Nitre (potasium nitrate) was needed for the manufacture of sulphuric acid. Nitre was imported from Chile (saltpetre) and in the last decades of the XIX Century from he desert of Peru and Bolivia.

Salt, essential product in the Leblanc method generally determined the location of the industries although this was not the only determining factor for the sites of the saltwort industries. The proximity of limestone and coal, energy to heat the furnaces and proximity to ports to receive saltpetre and pyrites also played an important role in site selection.

One of the greatest disadvantages that the Leblanc Method had over time as has been mentioned, was that after the second phase of the process, the sodium carbonate had to be extracted by means of leaching the masses yielded from the last melting. The resulting product, which did not dissolve in water, was therefore thrown away, it contained a large amount of calcium sulphate that, moist and buried in the landfills, was transformed an anaerobic process, into sulphuretted acid. The pestilent emanations of this made the air unbreathable around the areas close to these factories.

In Spain, there is no evidence that any saltwort production factories had been installed in which the Leblanc procedure was completed. As has been mentioned above only factories with reverberatory furnaces existed where sodium sulphate, coal and chalk was toasted.

VI. THE SOLVAY´S METHOD IN SPAIN

The procedure developed by Ernest Solvay, the ammoniac process, is based on the precipitation of sodium bicarbonate when common salt, ammoniac, dioxide of carbon and water react.

Several reasons determined that the Solvay´s enterprise et Compagnie established a saltwort factory in Torrelavega in the banks of Besaya river. Firstly, the presence of a salt deposit in Polanco (salt source). In second place, the fresh temperature in the necessary area to avoid increasing the refrigeration expenses. Thirdly the limestone mines in Quintana and Cuchía, and coal mines close to them. And finally, the proximity to commercial ports that made easy the delivery of manufactured products. It was also another reason that our country depended on the imported saltwort (England saltwort), since the end of the XIX Century. The importation was going to increase since 1865, and it was more pronounced from 1875 on, when the quantity is stabilised to the end of the century (58).

The first operation of the company was the acquisition in 1903 of the coal mines of Lieres, in order to ensure the energetic supply. The factory started building in 1904. The first saltwort is produced in 1908. Nowadays the factory works, though its configuration has changed almost completely. Paul Alban was its first manager.

It is advisable, even shortly, to comment on some characters about the saltwort by the Salvoy procedure, that gradually competed against others factories which used the Leblanc procedure.

The basis of the manufacture saltwort process by the ammoniac process, lies in constituting sodium acid carbonate (bicarbonate) from the mix of ammonium acid carbonate with a saturated dissolution of sodium chloride (brine). The chemistry reaction is:

The sodium bicarbonate softly charred is decomposed in neutral sodium carbonate (saltwort) and in carbonic anhydride. The ammonium chloride distilled with lime, produces ammonium. Either the carbonic anhydride or the ammonium, go back to the manufacture cycle.

In 1838, H.G. Dyar and J. Hemming attained an English patent to use this process. In 1839 Delaunay, who was their agent in France, carried out a French patent with the same purpose; and in 1840 he made another similar but more detailed, where the process is explained as currently carried out in large scale.

It was known, even before the Dyar and Hemming works that sodium bicarbonate could be prepared mixing common salt and acid carbonate of ammonium dissolution, but it was not given publicity. However, 100 Kg of saltwort were daily produced through this process in Turnbull and Ramsay factory in 1836. But one year later this method was no longer used. Something similar happened to the factory that Young built for James Muspratt in 1840. At that time in Kunheim in Berlin, Seybel in Vienna, and few years later Bowker in Leeds tried to overcome the serious problems of the process. New patents started to succeed between February and July 1854:Gossage, Turk, Schlösing and Deacon. H. Deacon and H. Gaskell built in Widness a factory that could produce several tones of saltwort, daily.

After having some economic loss, they transformed the factory and started working with the most secure and proven Leblanc process. Schlösing and Roland built a factory near to Paris in Puteaux, which was also a failure. They produced more than 300 tones of saltwort, but the defects in the plant made them stop producing with this process (59).

No more proves were made until 1863 that Ernest Solvay attained to apply to the industry the process that Dyar and Hemming described in their patent. This year, this Belgian resourceful chemist installed the first factory, called fábrica madre (mother factory) in Couillet, not far from Charleroi, in 1865. In Germany Honighann and Gerstenhöfer were the initiators in Germany. In the spring of 1874 through the Solvay process was obtained saltwort, in Winnington (England) (60). In France in 1883 some factories worked in St. Denis, Kille, Dombasle, Sorrgues and Giraud. The factories multiplied, some of them being independent from Solvay (61).

In 1890 the price of the saltwort dropped a 50% (62). Around 1895 the Solvay process used the same quantity of salt as the factories using the Leblanc process (63).

In Spain the process was already known. In 1858, when the activity had slack, an article published in the Variedades section in the magazine "Revista Minera", commented that "the direct extraction of the saltwort from the sea salt...is based on the chemical reaction of the ammoniac and the carbonic acid over the sea salt". This article regarded M.Schlaesing [Schlösing] as author of the process. It explains that "...an ammonium flow and another of carbonic acid, this one in excess, passed over a common salt dissolution. It can be formed several kinds of salts, such as sodium chloride, ammonium chloride, ammonium bicarbonate and the sodium bicarbonate, the least soluble. As a consequence of the Berthollet law, this salt is formed and lied, picked up, washed and charred to be transformed in sodium carbonate, which is used in the commerce" (64).

The reaction is reversible and takes place in low temperature, from left to right because in these conditions the sodium bicarbonate, which is little soluble, precipitates. If the temperature is high, and generally, when the volatilization of ammonium carbonate is possible, the reaction takes place form right to left. In the same way, in very low temperature, precipitates the sodium bicarbonate as well as the ammonium chloride. This circumstance is very important for the process, moreover the theoretical quantity from 110 to 115 Kg. of sodium chloride for 100 Kg. of sodium carbonate of 97 to 99%, must be much higher (200 to 220 Kg.)

The procedure has different parts. The first one is the preparation of the sodium chloride dissolution. The brines available are used if they are very concentrated and preferably saturated. Sometimes they were passed on salty box. The ammonium carbonate was used for taking out the iron, calcium and magnesium salts. With this purpose, we used the water of dissolution that has been used in the washing of diluted gas.

The second operation is the preparation of the ammoniacal salty bleach. When gaseous dry ammonium puts in contact with a saturated dissolution of common salt, it is precipitated. This happens because of the low solubility in the ammoniacal water, and because it also heats the dissolution and got it dilated. Sometimes the brine acquires a big amount of water that diluted considerably. This is due to the reaction between light bleach and the moist ammoniac from the decomposition of the ammonium chloride. This is the reason why the brine needs salt after the saturation with ammonium. To carry out this process it used the Fassbender saturator and in 1872 Solvay designed a specific instrument.

The next step is the treatment of the ammoniac brine with dioxide of carbon. Before this, the ammoniac brine has to cool down, since its reaction with dioxide of carbon gives heat off. The dioxide of carbon is obtained in furnaces, where lime stratums are alternate. This lime has to be as rich as possible in carbonate and cok, almost free from sulphur and producing little ash when is burnt. The most fitted cok was the one coming from the factories of lighted gas. The dioxide of carbon produced in the furnace was cooled and cleaned of impurities. Later it was injected with blower machines and was cooled again.

Afterwards the precipitation of sodium bicarbonate carried out. The Solvay precipitation tower was the solution to the difficulties appeared in this part of the process. It was so efficient that it still uses nowadays.

The separation of sodium bicarbonate from the bleach of ammonium chloride is done in adequate temperature, so that it can be filtered because of the granular-crystalline state of the sodium bicarbonate. Solvay took out the content of the absorption tower every half and hour, made it pass through vacuum filters. Iron cylinders of 3 metres diameter and 1,5 high constituted these filters, in which there was a grillage of wool covered with a wire netting. Later the bicarbonate was washed with cold water in order to take the ammoniac smell out.

The treatment to transform sodium bicarbonate into neuter carbonate was made in furnaces of calcination. Once the saltwort was charred, it is cooled, granulated and packed in barrels or sacks.

The dioxide of carbon given off in the calcination, is cooled in tubular coolers and introduced in the manufacture. In the treatment of the bleach of ammoniac chloride is obtained volatile ammoniac, used for the manufacture and decomposition of ammonium chloride. With this purpose, Solvay distilled the bleaches off from lime. He used the quicklime the way is obtained in the furnaces of whitewash of lime. He recommended slaking the lime with dissolution of calcium or magnesium chloride. So, it was obtained a pimply product that reacts easily with the bleach of ammonium chloride. Solvay also designed an instrument to recover the ammoniac. The product obtained after the distillation is calcium chloride, the only residuum not reused in the process.

ACKNOWLEDGES

For the carrying out of this paper I have counted on the invaluable help of my great friend Miguel Angel Yanguas, who offered to me excellent information and some clues to follow the history of the modern fabrication of saltwort. To thank Mr. Manuel Bartolomé García of the Solvay S.A (plc), who so kindly supplied me with the information about the factory of Torrelavega and the pictures that illustrate this paper. And finally, I am very grateful to Carmen Acebal Sarabia for her kindness in the revision of the chemical questions.

WORKS CITED

1. L. Mumford: "Technics and Civilisation" (1934) pags.109-110.
2. Cfr."Histoire Naturelle de Pline, avec la traduction de M.E.Littré". Paris. J.J.Dubochet.1850. Volume II, pag. 530. The glass replaced the selenite (crystallized gypsum) from Segóbriga. The latter had a prohibitive price because of the extraction and transport prices.

3. Cfr. Francisco Ximénez. " Quatro libros de la Naturaleza, y Virtudes de las Plantas, y Animales que están recevidos en el uso de la Medicina en la Nueva España". México. Diego López Dávalos. 1615, pag.203

4. Cfr. Pedacio Dioscorides: "Acerca de la Materia Medicinal" Translated and commented by Andres Laguna. Salamanca. Mathias Gast.1566, pag.549

5. Cfr. Giovanni Francesco Gemelli Carreri: "Viaje a la Nueva España". Preliminary study by Francisca Perujo. Mexico. U.N.A.M.1983, pag.105. Edition translated of the VI Volume from the book of Gemelli "Giro del Mondo".

6. Cfr. Antonio de Ulloa: "Descripción de una parte de Nueva España". This document is included in the book edited by Francisco de Solano: "Antonio de Ulloa y la Nueva España". Mexico. U.N.A.M.1987, pag. 119

7. See Francisco Ajofrín: "Diario del viaje que por orden de la Sagrada Congregación de Propaganda Fide hice a la América Septentrional en compañía de Fray Fermín de Olite, religisos lego y de mi provincia de Castilla" (1763). Biblioteca de la Real Academia de la Historia de Madrid. 9/3419

8. See Joseph Garcés y Eguía: " Nueva Teórica y Práctica del Beneficio de los Metales de Oro y Plata por Fundición y Amalgamación". Mexico. Mariano Zúñiga. 1802. In the chapter dealing with the " Cultivo de los tequesquites" , Garcés says that the best one for his melting method , is striped of sand, but joined to sea salt.

9. Miguel del Barco: " Historia Natural y Crónica de la California (Adiciones y correcciones a la noticia de Miguel Venegas)". Miguel León-Pinilla edition. Mexico. U.N.A.M.1988, pag.160

10. In the "Tesoro de la Lengua Castellana o Española"(1611) de Sebastián de Covarrubias, does not appear the "barrilla" word, but "soda" does. It says: "Plant from which ash was made glass", and saltwort: " Plant used for obtaining glass".

11. See Joaquín Fernández Pérez e Ignacio Gonzaléz Tascón: " Las plantas barrilleras. La obtención de la sosa y la potasa" in "La Agricultura Viajera" Madrid. Lumwerg.1990, pags.213-237.

12. See Ginés López González: " La obra botánica de Löfling en España" y Joaquín Fernández Pérez: " Tres apóstoles de Linné en Cádiz: Pehr Ösbeck, Pehr Löfling y Clas Alstromer" in "Pehr Lófling y la Expedición al Orinoco (1754-1761)" Ed.F.Pelayo.Madrid, Sociedad Estatal Quinto Centenario. 1990, pags.33-49 and 51-102.

13. Antoine de Jussieu: "Histoire de Kali d'Alicante" Memoires de l'Academie des Sciences.1717,pags.73-78

14. Cfr. Mariano La Gasca: "Del cultivo y aprovechamiento de la barrilla, salicor, algazul, sosa y otras plantas saladas" en Agricultura General de Gabriel Alonso de Herrera" Madrid. I.Real.1818, pag.237

15. We can find one more full list of species, which were burnt in Spain in Joaquín Fernández Peréz e Ignacio González Tascón: "Las plantas barrilleras" op.cit.pág.226

16. Nicolás Monardes: "Primera y Segunda y Tercera Partes de la Historia Medicinal de las cosas que se traen de nuestras Indias Occidentales que sirven en Medicina". Sevilla. Alonso Escribano.1574,pags.105 and 106

17. See "Relación Histórica del Viaje que hizo a los Reynos del Perú y Chile el Botánico D. Hipólito Ruiz en el año 1777 hasta el de 1788, en cuya época regresó a Madrid" Corrected and completed edition by Jaime Jaramillo-Arango. Madrid.Real Academia de Ciencias.1952.pag. 31

19. Antonio Alcedo y Bejarano: "Diccionario Geográfico Histórico de las Indias Occidentales o América. Es a saber de los reynos del Perú, Nueva España, Tierra Firme, Chile y Nuevo Reyno de Granada" Preliminary investigation by Ciriaco Pérez Bustamante. Madrid. B.A.E.1967 (4vols.) Volume III, pag.343. The first edition of the work of this erudite from Quito, was published in Madrid between 1786 and 1789.

20. Cfr. "Relación Histórica del Viage que hizo a los Reynos de Perú y Chile el botánico Don Hipólito Ruiz." Op.cit.pag.55

22. Susana Aldana: "Empresas coloniales. Las tinas de jabón en Piura". Lima 1988. In this book indicated that the bleach used for providing the soap's factories from Piura (Perú), were obtained sliding water over the ashes of the "lito" grass. (pag.36)

23. Cfr.Alejandro de Humboldt: "Ensayo político sobre el Reino de la Nueva España" Preliminary study byJuan A.Ortega y Medina. Mexico. Porrua. 4th Edition.1984.pag.459

24. See Joseph Antonio Varcárcel: "Agricultura General, y Gobierno de la Casa de Campo" Valencia. José Estevan y Cervera. 1795, Volume X, pag.33

25. The articles about "barrilla" are not very abundant, although most of the treaties on chemistry, arts and industries from that time commented on it. The details about the elaboration of the "barrilla" are usually too imprecise. This is the case of Soude article of the "Encyclopedie Methodique. Arts et Métiers Mécaniques". The most important article is written by Mariano La Gasca: " Del cultivo y aprovechamiento de la barrilla, salicor, algazul, soa y otras plantas saladas", that is an addition to the "Agricultura General de Gabriel Alonso de Herrera". Madrid. I. Real. 1818, pags. 228-311. There is a brochure also written by Mariano La Gasca titled: "Memoria sobre las plantas barrilleras de España" Madrid. I. Real. 1817. This brochure is exactly the same as the addition mentioned before, except in some introductory pages, "al lector", where the famous botanist explains how between 1810 and 1813, when he practised as military doctor, and being with his regiment in Cuevas de Overa, Orihuela and Murcia, he started being interesting in the saltwort production plants. The difficulty that exists in finding this brochure nowadays, makes me give the pages number in which can be find the edition of the "Agricultura de Herrera". They have also interest on this topic the following articles: "Carta sobre el cultivo y provechos de la barrilla" (by Manuel Eusebio García, a Níjar farmer) Semanario de Agricultura y Artes. 1806, Volume XII, pags. 113-118 and 137-142; Joseph Antonio Valcárcel: "Agricultura General y Gobierno de la Casa de Campo". Valencia. José Estevan y Cervera. 1795, Volume X, pags. 28-40; Rozier: "Curso Completo o diccionario Universal de Agricultura. Traducido por Juan Álvarez Guerra. Madrid. I. Real. 1799 (the edition of this dictionary started in 1842 includes a part that does not appear in the first edition, which is almost the literal copy of the article written by La Gasca, and as frequent it does not appear the source. The traveller and diplomat Jean François Bourgoing points out, although in a very short way, that some details about the barilla elaboration in his "Nouveau Voyage en Espagne ou Tableau de l´etat de cette Monarchie" Paris. Regnault. 1788, Volme II, pag.53.

26. Cfr. Mariano La Gasca. "Del cultivo y aprovechamiento de la barrilla"op.cit.pag 247.

27. See about cheating in the "barrilla" in the article by Joaquín Fernández Pérez e Ignacio González Tascón: "Las plantas barrilleras. La obtención de la Sosa y la Potasa". In "Agricultura Viajera". Madrid. Lumwerg. 1990, pags.213-237

28. Cfr. Mariano La Gasca. "Del cultivo y aprovechamiento de la barrilla"op.cit.pag 229.

29. The data has been obtained from Antonio José Cavanilles: "Observaciones sobre Historia Natural, Geografía, Agricultura, Población y Frutos del Reyno de Valencia". Madrid.I.Real. 1795-1797 (2 vols.)

30. The data that appears at the foot of page in the article of La Gasca op.cit.pags.250 and 251.

31. Cfr. Anselmo Payen: " Curso de Química Elemental e Industrial" Translated by Antonio González Bustamante y Miña. Madrid. Vda. de Calleja. 1842. Volume I, pag. 277

32. Cfr. Mariano La Gasca: "Del cultivo y aprovechamiento de la barrilla" op.cit.pag.251

33. J. Piqueras has obtained the data of documentary material in: "La Agricultura valenciana de exportación y su formación histórica". Madrid. Instituto de Estudios Agrarios, Pesqueros Alimentarios. 1985, pags.29-32

34. Ibid. Pag. 31. Madoz indicates in his Diccionary, probably making a mistake, that 1.564 "arrobas" went out from the Port of Alicante in 1843, and 2.436 "arrobas" in 1844.

35. Ibidem. J. Piqueras has obtained the data in the Legajo 2.220 from finance section of the Archivo Histórico Nacional.

36. See "Memoria sobre el estado de la Minería del Reino en fin del año 1845" presentada al Gobierno de S.M. por el Director General del Ramo" Anales de Minas, Volume IV, pags. 403-506, 1846

37. Let's see about the productivity of the barrilla in the article by Joaquín Fernández Pérez e Ignacio González Tascón: " Las plantas barrilleras.."op. cit.pag. 233.

38. La Gasca indicated that the manufacturer of precision's instruments, John Dollond, has been carried out a report, which indicated that the barilla from Alicante was the most suitable to obtain transparent glasses despite its impurities.

39. Cfr. José Canalejas y Casas: "Anuario de los Progresos Tecnológicos de la Industria y de la Agricultura". Madrid. L. Bailly-Bailliere. 1863. VolumeII, pag. 153.

42. Cfr.Ramón Torres Muñoz: "Tratado de Química General y Descriptiva " 5ª Edition. Madrid. R. Fe. 1885, pags. 571 and 572.

43. Cfr. Revista Minera: "Estadística Minera de España correspondiente al año 1863". Volume XVII, pag. 140. 1866.

44. All the data has been obtained by Juan de Vilanova y Piera: " Salinas de Villarrubia de Santiago" Annals of the Sociedad Española de Historia Natural, IV, pags. 89-93, 1875 and in "La Creación. Historia Natural" Barcelona Montaner y Simón. 1876, Volume VIII, pags. 58 and 59; and Salvador Calderón: "Origen de la sal común y de los sulfatos de los terrenos terciarios lacustres de la península". Annals of the Sociedad Española de Historia Natural, Volume XXIV, pags. 337-362. 1896.

47. See José Grande: " Sobre el Estado de la Minería del Distrito de la Provincia de Burgos en Agosto de 1846" Anales de Minas, Volume IV, pags.235-249, 1846.

52. D.W.F.Hardie y J.D.Pratt: "A History of the Modern British Chemical Industry". 1966, pag. 19.

53. C.C.Gillespie: "The Discovery of the Leblanc Process" Isis, 48, pags.152-178, 1957.

55. In order to get more details about the the development of the saltwort industry in England, see Kenneth Warren: "Chemical Foundations: The Alkali Industry in Britain to 1926". Oxford. Clarendon Press. 1980.

59. See " Gran Enciclopedia de la Química Industrial Teórica, Práctica y Analítica" (Muspratt Chemistry). Barcelona. F. Seix. s.a. Volume XII, pag. 711-776 and "Enciclopedia de Química Industrial", directed by the Prof. Dr. Fritz Ullmann. Versioned by José Estalella. Barcelona. G. Gili. 1931. Volume III, pags. 505-546.

61. See Jacques Bolle: "Solvay. El invento, el hombre, la empresa industrial. 1863-1963". Bruselas. Ed. Weissenbruch. 1963 and Maxime Rapaille: "Solvay. Un gigante" Bruselas. Didier Hatier. 1990.

ANTILIA

FROM THE BARRILLA TO THE SOLVAY FACTORY IN TORRELAVEGA: THE MANUFACTURE OF SALTWORT IN SPAIN

Joaquín Fernández Pérez