Collegium ...

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1902 - Leather
 

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Page 281 - ... fraude, qui est pratiquée impunément; car on n'a pas de procédé chimique permettant de la reconnaître. Nous avons appliqué la réaction de l'acide iodique à la recherche et au dosage de l'extrait de châtaignier en mélange dans l'extrait de chêne. On procède à la recherche qualitative en mélangeant par retournements successifs dans une boule à robinet, la solution d'extrait suspect avec une solution d'acide iodique et du sulfure de carbone; si le sulfure de carbone présente une...
Page 70 - Place 2 grams, if it be an extract, in a fiat-bottom dish not less than 6 cm. in diameter, add 25 cc of water, warm slowly till dissolved, continue evaporation, and dry. b) All dryings called for, after evaporation to dryness on water bath or others, shall be done by one of the following methods, the soluble solids and non-tannins being dried under similar and, so far as possible, identical conditions : 1. For eight hours at the temperature of boiling water in a steam bath.
Page 110 - ... state the heartwood only) is reduced to' chips and boiled with water in earthen jars over a mud fireplace. As the liquor becomes thick and strong it is decanted into another vessel and the evaporation continued till the extract will set on cooling when it is poured into molds made of leaves or clay, the drying being completed by exposure to the sun and air.
Page 281 - Nous avons constaté que, si l'on agite à froid une solution d'extrait de bois de châtaignier avec une solution d'acide iodique, une certaine quantité d'iode est mise en liberté, tandis qu'avec l'extrait de bois de chêne on n'observe rien de semblable. La réaction est également négative avec les solutions de québracho...
Page 71 - F. Swedish recommended) of size sufficient to hold entire filtrate, returning till clear. Evaporate 100 cc of the filtrate. The weight of the residue must be corrected for the dilution caused by the water contained in the wet hide powder.
Page 70 - IV. TOTAL SOLIDS. Shake the solution, and without filtering immediately measure out 100 cc with a pipette, evaporate in a weighed dish, and dry to constant weight, at the temperature of boiling water. Dishes should be flatbottomed, and not less than 6 cm. in diameter.
Page 70 - I. PREPARATION OF SAMPLE. Barks, woods, leaves, dry extracts, and similar tanning materials should be ground to such a degree of fineness that they can be thoroughly extracted. Fluid extracts must be heated to 50° C., well shaken, and allowed to cool to room temperature.
Page 71 - ... through linen, squeeze thoroughly by hand, and remove as much water as possible by means of a press, weigh the pressed hide, and take approximately one-fourth of it for moisture determination. Weigh this fourth carefully and dry to constant weight. Weigh the remaining three-fourths carefully and add them to 200 cc of the original solution ; shake ten minutes, and squeeze the tanned hide through linen.
Page 71 - ... chrome alum in solution, this solution to be added as follows: One-half at the beginning and the other half at least 6 hours before the end of the digestion. Wash by squeezing through linen, continue the washing until the wash water does not give a precipitate with barium chloride. Squeeze thoroughly by hand and remove as much water as possible by means of a press, weigh the pressed hide, and take approximately one-fourth of it for moisture determination. Weigh this fourth carefully and dry to...
Page 71 - To a small portion of the clear non-tannin filtrate add a few drops of the filtered tannin solution. A cloudiness indicates the presence of soluble hide, in which case repeat the process described under 6, giving the hide powder a more thorough washing.

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