92 ORD. XLI. Scabridz. HUMULUS LUPULUS. 
separate those that are defective from those that-are sound ; both kinds are 
carried to the kiln (for the purpose of drying) as soon as possible after they 
are gathered. The heat of the kiln requires to be regulated with great 
nicety, to prevent their being dried too rapidly. To obviate this occurrence, 
many kilns have two floors, on the uppermost of which the greener hops are 
laid, and gradually dried, before being brought to support the heat of the 
lower floor. Charcoal is usually employed, as the other kinds of fuel are 
said to injure the flavour of the hops. The strobiles are considered suffici- 
ently dried when they become crisp; but they acquire some degree of te- 
nacity and toughness, from lying in heaps on the floors of the store-houses, 
previous to their being bagged. 
Sensible and Chemical Properties. The dried strobiles have a peculiar 
fragrant odour, and a very bitter, somewhat aromatic, and slightly astrin- 
gent taste. New hops are of a pale, greenish-yellow hue, and appear like 
thin, transparent leaves; by long keeping their colour changes to a yellow- 
ish-brown. The watery infusion has a pale straw colour, is rendered muddy 
by the mineral acids; alkalies deepen its colour; it strikes an olive with 
sulphate of iron, is precipitated by solutions of nitrate of silver, tartarized 
antimony, superacetate of lead, and alcohol: and when rubbed with mag- 
nesia, or lime, a rod dipped in muriatic acid discovers the presence of am- 
monia. By distillation in water, an essential oil is obtained. The virtues 
of hops are extracted by alcohol, ether, and boiling water; by long boil- 
ing the aromatic properties are dissipated. : 
From the experiments of Dr. Ives of New York, it appears, that the active 
properties of hops reside in a powder, which may be readily separated from 
the strobiles, by merely sifting in a fine sieve. This substance forms about 
one-sixth part of their weight, and to it Dr. Ives has given the name of Ju- 
' pulin. According to Dr. Ives’ analysis, 120 grains of lupulin contain about 
—of tannin 5 grains, extractive 10, bitter principle 11, wax 12,.resin 36, 
lignin 46. The extractive matter is soluble in water only; the bitter prin- 
ciple is soluble in alcohol and water; the wax soluble only in the alkalies 
and boiling ether ; the resin soluble in ether and alcohol; the aromatic and 
bitter properties of the lupulin are more readily and completely imbibed by 
alcohol than by water, and much sooner by both when hot than when cold ; 
about fiye-eighths of lupulin are soluble in water, aleohol, and ether, three- 
eighths being vegetable fibrous matter. M. Payer, and A. Chevalier have 
