VOL. LXXXIV.] PHILOSOPHICAL TRANSACTIONS. 433 



in the preceding experiment. White lac was also distilled from pot-ash, without 

 any material difference in the result, excepting that the oils which distilled over 

 were thicker. 



V, Experiments on the Liquid contained in White Lac. 



(a) On pressing, between the fingers, the pieces of white lac, in the state in 

 which they are taken from the tree or shrub (though they are apparently quite 

 dry and brittle, and have been kept several years), a watery liquid oozes out ; 

 by which paper stained with turnsole is instantly turned to a red colour, (b) 

 The 550 grs. of reddish watery liquid above-mentioned, as separated from 2000 

 grs. of white lac, were filtrated through paper in order to separate mucilage, 

 (aa) This filtrated liquid has a slightly saltish taste, with bitterness, but is not at 

 all sour, (bb) When made hot, it smells precisely like newly baked hot bread, 

 (cc) On standing it becomes somewhat turbid, and deposits a small quantity 

 of sediment, (dd) Its specific gravity in the temperature of 6o° was to distilled 

 water as 1025 to 1000. (ee) A little of this liquid having been evaporated till 

 it got very turbid, on standing afforded small needle-like crystals in mucilagi- 

 nous matter. 



(c) About 250 grs. of the liquid (b) were poured into a retort which held 1 

 oz. measure, to which was joined a receiver containing 2 shreds of paper, one 

 stained with turnsole, and the other had been dipped in solution of sulphate of 

 iron. As the liquor got warm, mucilage-like clouds appeared, but when it be- 

 came hot they disappeared ; and about the temperature of 200° it distilled over 

 very fast. On distillation to nearly dryness, a small quantity of extractive mat- 

 ter remained. The distilled liquid while hot smelt like newly baked bread, and 

 was perfectly transparent and yellowish. The paper stained with turnsole was 

 not reddened ; nor was that which had been immersed in solution of sulphate of 

 iron turned to a blue colour on moistening it with ley of pot-ash. (d) The flame 

 of a candle being applied by means of a blow-pipe to the extractive matter (c), 

 the whole of it was burnt away, except what produced a black mark on the 

 spoon ; in which no trace of alkali was detected by paper stained with turmeric, 

 (e) About 100 grs. of the yellowish transparent liquid (c) being evaporated till 

 it became turbid, after being set by for a night, afforded acicular crystals ; which 

 under a lens appeared in a group, not unlike the umbel of parsley. The whole 

 of these crystals could not probably have weighed i gr. They tasted only 

 bitterish. 



(f) One hundred grs. of the yellowish transparent liquid (c) being evaporated, 

 in a very low temperature, to dryness, a blackish matter was left behind, which 

 did not entirely disappear on heating the spoon containing it very hot in the 



VOL. xvii. 3 K 



