Experiments and Olservatlons on Lac. 1 5 



E. Alcohol acted but feeblv on the reskUium ; it was 

 therefore put into a matr; ss^ with three ounces of acetic 

 acid, and was sufi'ercd to digest without heat during six 

 d:->ys, the vessel being at times gently shaken ; the acid thus 

 assumed a pale brown colour, and was very turbid. The 

 whole was then added to halt' a pint of alcohol, and was 

 digested in a sand-bath ; by which a brownish tincture was 

 formed, and at the same time a quantity of a whitish floe- 

 culent substance was deposited, which, being collected, 

 well washed with alcohol on a filter, and dried, weighed 

 20 grains. 



This substance was white, light, and flaky, and, when 

 rulvbed by the nail, it became glossy, like wax; it also 

 easdy melted, was absorbed by heated paper, and, when 

 placed on a coal or hot iron, emitted a smoke, the odour 

 of which very much resembled that of wax, or rather 

 spermaceti. 



F. The solution formed by acetic acid and alcohol beino- 

 filtrated, was poured into distilled water, which immediately 

 became milky ; and, being heated, the greater part :■>'.' the 



• xesin which had been dissolved assumed a curdy form, and 

 was partly separated by a filter, and partly by distilling off 

 the liquor ; this portion of resin an:ounte'd to 31 grains. 



G. The filtrated liquor, from which this resin had been 

 separated, was saturated with a solution of carbonate of 

 potash ; and, being heated, a second precipitate of glutea 

 was obtained, which, when well dried, weighed 9 grains. 



The 500 grains of shell lac thus yielded. Grains. 



A. Kxtract _ _ _ 2.30 



p* /Resin _ - . 454.50 



D. 

 G. 

 1'^. Wax - _ _ 20. 



I Vegetable gluten - - 14. 



491. 

 The mode of analysis adopted for the shell lac, must un- 

 doubtedly appear less smiplo than that which was employed 

 tor seed and stick lac; but, upon the whole, it was attended 

 with advantages ; for the shell lac being in small fragrnents, 

 and not in the state of a powder, considerablv facilitated 

 the dccantation of the solution in alcohol from the resi- 

 duum ; and although, in this last, a portion of the retain 

 was nrotfcttd from the action of the alcohol, by being 

 enveloped in the gluten and wax, yet, bv the assistance of 

 acetic acid, tlie remainder of the resin, as well as the wholf 



•of 



