42D 
Glue. 
pared from the membranous and cartilaginous parts of 
animals, and after being dried, they were melted into 
tablets. It is certain, however, that every animal sub- 
stance containing jelly may be used in the manufacture 
of glue ; and, according to Duhamel, a strong but black- 
coloured glue may be obtained from bones and hartshorn, 
after they are dissolved in Papin’s digester. The Eng- 
lish glue, is reckoned far superior to any kind manufac- 
tured abroad, and furnishes an article of exportation to 
the continent ; and the Dutch society of arts and manu- 
factures have long offered premiums for a specimen equal 
to the English, the Flanders glue being considerably in- 
ferior to that manufactured in England, and that manu- 
factured in France is still worse. 
From the experiments of Parmentier, it appears that 
six pounds of button-maker’s raspings yielded a pound 
of excellent glue, not inferior to that which is manufac- 
tured in England. The glue which he obtained from 
the filings of ivory was equally good, but more highly 
coloured. The filings of horn yielded none of this sub- 
stance. To obtain glue as colourless as possible, a very 
small quantity of water should be employed for extract- 
ing the jelly, by which means it may be concentrated 
without long evaporation, as exposure to heat has always 
a greater or less influence on the colour in proportion to 
the time. The whiteness and transparency of the Flan- 
ders’ glue are said to originate from an adherence to this 
plan. 
In their consistence, colour, taste, smell, and solubi- 
lity, glues are found to differ from each other consider- 
ably. Some glues will dissolve by agitation in cold water, 
while others are only soluble at the point of ebullition. 
It is generally admitted that the best of glue is transpa- 
rent, of a brownish yellow colour, and having neither 
taste nor smelL It is perfectly soluble in water, forming 
