Lot n° 289
200 - 300 EUR
TANNING. Manuscript, Notes pour l'application... - Lot 289 - Ader
TANNING. Manuscript, Notes pour l'application du procédé de tannage de Mr Félix Boudet, [ca. 1840]; 5 pages in-4, marginal annotations in ink or pencil. Presentation of a new tanning process. Tanning, which consists of treating the hides to transform them into leather, is made up of 4 distinct operations: pelting, depilation or de-hairing, swelling, and tanning proper, or pitting. Around 1840, the pharmacist Félix BOUDET (1806-1878) improved the first two operations by substituting lime with caustic soda, which made it possible to obtain softer leathers in half the time: "We will have to press fourteen kilos. of soda ash crystals, break them up, crush them, dissolve them in about fifty litres of water, and then, when the solution is complete, add seven kilograms of anhydrous caustic lime, which will have been previously slaked and then diluted with sufficient water to form a fluid slurry. This mixture should be made in a tub or barrel with a lid, in which it should be left for at least six hours so that the soda crystals can be completely decarbonated. Then] the whole mixture is poured into a tank, in other words into the plain, in which fifteen to sixteen hundred litres of water have been put beforehand [...]. When this is done, the skins will be thrown successively into the plain [...], taking care to spread them out in layers as much as possible, and they will be left in contact with the liquor for 36 or 48 hours, more or less, until the hair comes off easily"... Etc.
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