388 MR C. G. WILLIAMS’ RESEARCHES ON 
solution of chromic acid being quite dissimilar, for while chinoline and its salts 
gave a beautiful orange-yellow crystalline precipitate, leukol was oxidized and con- 
verted into a black resinous oil. Subsequently,* Lizsic announced, upon the au- 
thority of experiments made by Hormany, that perfectly pure leukol gave the 
same crystalline precipitate with chromic acid. I have not been so successful as 
M. Hormann; for, although the chinoline and lepidine procured by destructive 
distillation from cinchonine have, in my hands, given salts of extreme beauty and 
purity with chromic acid, I have failed to obtain the same result with either the 
chinoline or lepidine from coal-tar. I have also boiled the bases from the latter 
source with dilute chromic acid, to destroy impurities, and then separated them by 
distillation with potash, but they merely gave an oily precipitate with chromic acid. 
When dissolved in hydrochloric acid, and bichromate of potash is added, the same 
result occurs. I even took a platinum salt of coal-lepidine, which yielded, on com- 
bustion, the numbers detailed in Analysis I., p. 398; and, after having reobtained 
the base by distillation with potash, endeavoured to procure from it a crystalline 
chromate, but in vain, a red oil being the only product. It is true, that when I 
added dilute chromic acid to chinoline from coal-tar, the sides of the tube acquired 
a coating of very minute brilliant points, which reflected light with a peculiar 
satin-like lustre; but the lens resolved them into oily globules. The following 
experiments were, therefore, made upon chinoline from cinchonine. Neither GER- 
HARDT nor Hormann have analysed the salt. 
The beauty of the bichromate of lepidine described in my last paper, induced 
me to ascertain the composition and properties of the homologue next below it, 
in the anticipation that its outward appearance would be equally striking. But 
there are some slight differences in the two bodies; bichromate of chinoline is 
still less soluble than the other salt, and this prevents the crystals from being 
readily procured of so large a size. When dry, it is much more violently decom- 
posed by heat than the lepidine compound. The fixed product is, however, the 
same, namely, green oxide of chromium and carbonaceous matter. If the dry 
salt be placed in a capsule, and heat be very gradually applied, no change at first 
takes place, but suddenly it takes fire with explosive violence, and the greater 
part of the green oxide and carbon is projected. I prepared the salt for analysis 
by adding dilute chromic acid in excess to pure chinoline; at first the product is 
somewhat resinous, but immediately it is touched with a glass rod, it becomes 
gritty and crystalline. The solid is then filtered off, the mass slightly washed, 
dissolved in boiling water, filtered to remove traces of an oily impurity, and, on 
cooling, the fluid becomes filled with brilliant yellow needles arranged in groups. 
It may be dried at 212° with safety, provided adhering moisture has been re- 
moved as much as possible by pressure between folds of filtering paper. If the 
* Chem. Gaz., vol. iii., p. 251 (1845). Proc. of Chem, Soc., April 7, 1845. 
+ Trans. Roy. Soc. Edin., vol. xxi. part ii, 
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