The ancient tanneries

The ancient tanneries are located on the left bank of the River Temo, and in 1989 they were declared a national monument. Today you can admire the ancient buildings that once housed the ancient vocation of the town of Bosa. The Count of Marmora describes the ancient tanneries for the first time as the complex ‘Sas Conzas’, set in the valley crossed by the Temo, where the town of Bosa lies.
This is a row of two-storey buildings, built in the mid nineteenth century, with pitched roofs and large windows. They were built far away from town because of the bad smells produced during the early stages of the leather production, and they were strategically placed near the river for the water supply, as water is used in the production process. The tanneries are testimony to the town’s middle class, modern and dynamic age of Piedmont and post-unification, in great contrast to the Spanish era.
The tanning tradition in Bosa dates back to the Roman times, if not earlier, and was present until the mid-twentieth century when the last tannery closed its doors permanently. The production, specifically of cow leathers such as in the use of bookbinding, was advanced and highly regarded in the area and abroad. It is therefore obvious that Bosa was a great exception when you consider that around 1870 there was a sharp deterioration in the relationship between import and export in Sardinia. The trade of leather from Bosa to Genoa and France went on continuously throughout the nineteenth century. The uniqueness of the Bosa territory was not only due to the innovations of its manufacturing systems as its also developed a modern business organization who, by concentrating ownership in a few families, eliminated the marked fragmentation of production in the first half of the nineteenth century. The 28 companies registered by the father Vittorio Angius in 1834, in the Dictionary of Casalis, shrank to 23 in 1860 and to 15 in 1887. With the company of the Brothers Solinas and Mocci Marras on one side and the company of Sanna Mocci on the other the process of industrial concentration started that ultimately led to the last family deal (around 1950) with the large enterprise of the leather tanning town. These changes, in addition to the political and ideological context of Bosa at the time, were responsible for the establishment of the Workers' Mutual Aid, in 1868, which was an organization particularly involved in the defense of workers in the leather trade and included tanners, saddlers, shoemakers, and coopers.
During the time of the first English industrial revolution, Mocci Marras began to dismiss the workers who would not buy meat and agricultural products from his store. The workers then responded with a somewhat modern defense weapon: the strike of 1902, as noted by Girolamo Sotgiu. By the time of the Second World War, in 1942, the Solinas and Mocci Marras companies had disappeared and the brothers Sanna Mocci, which had a production capacity of 30 tons per month of leather, joined with the tannery of John Contini (15 tons per month), each event due to the effect of the war. Of these two tanneries, including those in the province of Nuoro, Sanna Mocci was the only one fully equipped and able to respond (S. Ruju, 1988). The activity of the Sanna Mocci Company, widely known in Sardinia, received one of the last recognitions for the Sardinian tanning industry from outside of the island, as the company was assigned to the international exhibition in Rome in 1924, which is considered the grand prize and the gold medal. Since the beginning of the twentieth century, acquiring most modern machinery by the Zanelli Company of Turin, the Sanna Mocci had even further revolutionized the manufacturing systems. They used ‘erodina’ instead of dog excrement, introduced drums to shake the skin (which was first stirred with sticks by workers), used cylinders to move the leather, and then utilised ‘palmellatrici’, bleaching and iron to smooth the skin. They continued to use the renowned iron: ‘de ilmasciare’, which was used to remove the hair from the skin along with a piece of stone (‘de iscaranare’) for the stripping, ‘de bussare’, to stretch after at least four months of work, and ‘de rasigare’ for the last finishing (E. Sanna 1977). From the sixties onwards, the process should have been modernised and improved, however no one had the strength or interest to go ahead with this and therefore the permanent closure of tanneries was announced.
Architectural and urban planning - The tanning industry in Bosa is located on the left bank of the river Temo due to need for large quantities of salt water during the leather manufacturing process. The long row of buildings were architecturally reworked in the nineteenth-century and consist of two-storeys with drums side by side. Inside the tannery, on the ground floor, they used at least one masonry tanks to begin the processing the leather. As the upper levels where more dry, this is where the finishing stages of the process took place. The buildings consist of supporting walls made out of stone and mud, or stone and lime, which are then plastered and painted with lime and dust ‘trachytic’. Trachyte liparitica (a type of rock) or local varieties of rose, was used for the tread of the stairs, doorposts, lintels of doors and windows, and also for other coatings and details of the interior.
The roof is made of Sardinian tiles and supported by wooden warping, and the first level is made of brick with sails and shelves. The buildings were arranged in a secluded spot, as the city was still enclosed by medieval walls, connected to the bridge by a door. Although within walking distance, they were separated from the town by the river as this distance meant that small particles of leather and tanning substances were removed from the air breeze before it could reach the houses. The tanneries were constructed by masons of Bosa who were regarded with great prestige in the past. The typical severity of the outer reflects the order and simplicity of the interior where there are working spaces on two floors, functional to the needs of organising production as well as providing a defence against the frequent flooding of the river.
The interior, with access to the upper floor by a staircase, consists of at least one adjoining rooms separated by arched openings. The large windows, covered with grates, allowed the leather to be constantly aired. The simple brickwork decor was diversified by the activity taking place on that particular level of the building, on the ground there were a series of basins (cuzos), built in masonry and wood-paneled oak or chestnut, the stand (on gallittu) in marble or wood, the water well, which was in the area of the basins, the drums of wood (for the "rapid tanning"), the marble tables and the press to remove water and unwanted tanning substances. In the adjoining room (the area known as ‘rusca’), was the mill where rind was ground (‘sa rusca’) to extract the tannin of the oak: the stone rollers (sas molas) were also placed in this area and were usually made of basalt from east of Crabalza, similar to olive mills. The movement was created by a horse, which was later replaced by an electircal machine. Upstairs the atmosphere was brighter and more airy. Here the furniture consisted of iron hooks anchored to beams on the roof, tables with marble top, machines to finish the job of tanning such as trimming, and the cylinder. Tools were hung from the wall which were used for any manual finishing (such as blades, and tools made from cork, cut crystal, and iron). On the same floor there was also various wooden boxes for the storage of leather, the weighing pivot used when selling, and the office used for administrative tasks (s'iscragnu).
The production cycle - Details of the production cycle can be gained from a series of photographs and information provided by witnesses (Francesco Biddau, Anna Sanna Biddau, Paul Ledda, Serafino Piras). In 1800, the leather used in Bosa’s tanneries came from local slaughterhouses and various parts of Sardinia. In the Second World War, however, skins also came from Africa (Mombasa, Nigeria). They tanned hides of oxen, cows, calves, and bulls, (which gave large leather for soles and harness’). The skins of Sardinian lamb was considered particularly excellent in Europe, (the hair was also for fur, through the "slow tanning" process if the skin was used for uppers). In the last century the skins were still being processed by the method of "slow tanning", a cycle which took six months. There were three processing steps: 1. Soaking (a modde) and steeping the skins in water, followed by putting them into lime and removing the hair, then the skin was re-immersed in water before removing the last residues of hair and fleshing. 2. The actual tanning involves scouring and myrtle - Scouring with dog excrement caused the eliminatory effect of the lime and gave the skin more elastic, subsequently dog excrement was replaced with an alternative product (erodina) consisting of an enzyme that produced the same result but without the hygienic inconvenience and bad smell of the original process.
3. Finishing: putting the wind. There were many tools used to smooth, comb and buffer the leather upon the marble table.

The method of "rapid tanning" involved a 45 day cycle and was adopted in 1920 by the tannery of the Sanna Mocci brothers. There were always three processing steps: 1. soaking in the pit with water (about 3000 litres): where the skins were kept in the tanks for 7 or 8 days, and care was taken to gradually replace the worn out ones with new rind, 2. tanning: hair removal (in drums), fleshing and scouring (in drums), tannin (in drums), lubrication (in drums), 3. finishing: putting the wind, ironing (by hand), trimming, and using the cylinder and tools described during the "slow tanning" process but instead with electricity.
The description of the production cycle is documented by photographs taken by Salvatore Sanna in 1958. With a wooden stick they turned the skins in the tanks (Calcinai), which were insulated with oak or chestnut wood to keep the tanks at a constant temperature. The hides were immersed in water and lime and had to be stirred every morning. It was important not to have any air bubbles, therefore weights were placed upon the hides. Then the job of fleshing was performed using the easel (on gallittu), and a knife with a curved blade (ferru de ilmasciare), and the skin which was placed flesh side up (palte de sa Petta). In the adjoining room there were four types of drum: for softening with lime and removing the hair, for greasing (with oil of peace) for tanning with tannin (plant product extracted from the bark of the oak: tannin was produced with a dark leather but excellent for the sole, without cracking, because it had the power to bring down the gelatin and transform skin leather), and a small drum for skin that you tanned in 8-12 hours depending on the season or skin type. In the same area, water and residue from the tanning process was removed from the skin by fixing it to the press (this process usually involved at least six workers). The skins were then ironed and stretched out on a marble table to dry.
The finishing phase began after the skins, drained and passed through the press, were hung to the ceiling beams and arranged so that they were well ventilated. The first step was to take the dry and ironed skins down using cutting tools, taking care not to damage the surface (they worked from the "flower"). You then shaved the skin (arrasare), cutting out the imperfections (dibudare) and thick parts. The following step was the trimming where a batter made ​​from fish oil, soap, cream and wax, was applied and left for 5 minutes until considered dry and ready to be softened. Then the skin was turned again, stretched, and sprinkled with talcum powder. Then, using crystal, pressure was put on the skin to make it smooth and restore the natural color. Finally there was the selection of skins (ranked 1st, 2nd, and 3rd choice) that were then folded into 4 pieces and placed in boxes, ready to be sold. The cylinder was also used in the last phase of finishing but only for leather soles. As remembered by Elio Vittorini as an infant in Sardinia (1931), there were many boats from Cagliari which united the commercial ports of the island. From the port of Bosa Marina, and by rail, the tanned leather departed for the Peninsula and France.

Elisabetta Sanna - from the book "LE CONCERIE DI BOSA" [TANNERIES OF BOSA]"