199 
Chemistry. 
ed by mixing powdered gulacum and wheat flour, employed 
M. Rudolph! to prosecute the inquiry. M. Rudolph! found, 
1 . That when the guiacum and pure starch are kneaded toge- 
ther, no colour is developed. % That the guiacum scarcely 
becomes blue when the flour contains little gluten, or when the 
flour has undergone any alteration in its qualities ; and, 3. 
That when gluten or zimome is kneaded with powdered guia- 
cum, the mixture assumes a very pure blue colour. Giornale 
de Physic. Sd Bimest. 1819. 
20. Indigo. — Dr Thomson has found that indigo, in the 
state of a greenish-yellow^ soluble pigment, is composed of 
5 atoms oxygen, - - 5.00 
7 carbon, - 5.25 
1 azote, - ^1.75 
12.00 
Ann. of Phil. No. xc. p. 467. 
21. Camphor. — Dr Thomson has found that camphor melts 
when heated to 288°, and boils at the temperature of 400. He 
ascertained it to be composed of 
8 1 atoms carbon, - - 6.375 
10 hydrogen, - - 1.250 
1 oxygen, - - 1.000 
8.625 
Ann. of Phil. No. Ixxxix* p. 392. 
22. New Alkali called Brucine. — This new alkali was disco- 
vered in the false Angustura bark ( Brucea anti-dysenterica ) by 
MM. Pelletier and Caventou, who discovered strychnine. (See 
Vol. I. of this Journal, p. 210.) When brucine is dissolved 
in boiling alcohol, and crystallised by spontaneous evaporation, 
it yields colourless and transparent crystals, in the form of 
oblique quadrangular prisms. 
23. Spontaneous Combustion of Cloth. — About 25 pieces of 
cloth, each of which contained nearly 30 ells, were deposited 
upon wooden planks in a cellar at Lyons, on the 8th July 1815, 
in order to conceal them from the armies which then overran 
France. In the manufacture of the cloth, 25 lb. of oil were 
used for a quintal of wool, and the cloth was quite greasy, each 
