106 Dr. Tveson the ChemicalProperties and Economical [March, 



bitter taste ; when filtered and evaporated, it yielded one dram 

 of extract, of the consistence of soft wax.* 



Exp. 4. — A saturated decoction of the lupulin was prepared 

 with pure water. It was opaque, and of a pale yellow colour. 

 By adding to a portion of it a solution of the sulphate of iron, 

 the colour was changed to a deep purple, approaching to black ; 

 a solution of animal gelatine threw down a copious ash-coloured 

 precipitate, which left the supernatant liquor transparent and 

 clear. This liquor was now decanted ; by adding to it a solution 

 of iron, it was changed to a pale blue , the acetate and subace- 

 tate of lead caused a copious curdy yellow precipitate ; the 

 nitrate of silver, a greenish flocculent precipitate ; muriate of tin, 

 when first added, produced no change, but after standing a short 

 time, a brown precipitate ; a solution of sulphate of alumine 

 caused no immediate change, but by boiling with the decoction, 

 it separated a dense precipitate. Silicated potash, alcohol, and 

 Tege table blue, induced no change. 



Exp. 5. — Two drams of lupulin in four ounces of water were 

 digested six hours in a sand-bath. The infusion yielded by eva- 

 poration six grains of aromatic and bitter extract. Tvv'o ounces 

 of proof spirit were added to the same lupulin, and subjected to 

 a moderate heat 12 hours ; when filtered and evaporated, there 

 remained six grains of a resinous extract. The same lupulin was 

 digested 30 minutes in boiling alcohol, from which was obtained 

 by evaporation 62 grs. of extract. The extract obtained by the 

 second process was soluble in pure alcohol, and when water was 

 added to the solution, it became turbid and milky. 



Exp. 6. — The lupulin used in the last experiment was boiled 

 in strong caustic ammonia. When filtered and supersaturated 

 with distilled vinegar, a copious precipitate ensued, which was 

 insoluble in alcohol, and possessed the sensible properties of an 

 impure wax. The last three experiments show pretty satisfacto- 

 rily that the most important proximate principles of the lupulin 

 are resin, wax, tannin, gallic acid, a bitter principle, and an 

 extractive matter. The following experiments were instituted 

 for the purpose of ascertaining more accurately their respectiv« 

 proportions as v*?ell as the aggregate amount of soluble matter in 

 a given quantity of lupulin. 



Exp. 7. — Two drams of lupulin were infused five hours in boil- 

 ing water. To the filtrated infusion were added, at intervals, 

 five grains of animal gelatin in solution, when it ceased to pro- 

 duce any precipitate, and the supernatant liquor became trans- 

 parent and clear. The sediment, when dry, weighed 10 grains. 

 An ounce of alcohol was added to the filtered solution, but it 



♦ These experiments, with some variation, were frequently repeated, with the view 

 to detect, if practicable, the volatile oil which is so frequently mentioned by authors at 

 essential to the flavour of beer. The result was uniformly the same. The peculiar 

 aroma of the hop was always obvious to the smeU and taste, but I was never able to sepa- 

 xate it in the form of an essential oiL 



