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CHINOLINE AND ITS HOMOLOGUES. 395 
to chinoline, develops much heat, and on evaporation at 212°, a crystalline mass 
was obtained, but so deliquescent, as to be unfit for examination. 
On the Chinoline Series as it occurs in Coal-Tar. 
In my paper “ On some of the Basic Constituents of Coal-Naphtha and on 
_Chryséne,” I ventured to express a belief, that chinoline was not the only mem- 
ber of the group to which it belongs present in coal-tar; and feeling assured that 
other homologues remained to be discovered, I was desirous of testing the accuracy 
of the supposition. Owing to the kindness of Mr Grorce Mitter of Dalmarnock, 
I was enabled to obtain fifty gallons of coal-oil of a very. high boiling point, and 
of a density greater than that of water. It was shaken with sulphuric acid to 
extract the alkaloids, and the acid fluid after dilution with water was treated with 
excess of lime, and distilled as long as any came over. As the amount of bases of 
the Dippel series present, was not large, the product being of such a high boiling 
point, I did not add potash to separate the more soluble portion, but only collected 
that part which, from its density and insolubility, sank to the bottom of the fluid 
accompanying it in the distillation. By means of a tap funnel, the basic-oil was 
separated from the chief part of the water accompanying it, which contained some 
of the pyridine series in solution. The bases thus obtained are exceedingly im- 
pure, and contain aniline and some non-basic substances. It being probable, 
_ that toluidine and even other members of the same series might be present, I 
thought that as apparently insurmountable difficulties prevented their separation 
from the chinoline series by means of oxalic acid, or similar methods, their 
presence might nevertheless be made manifest through their products of decom- 
position. With this view, I treated the mixed bases with nitrite of potash and 
hydrochloric acid, in the manner indicated by Hunt,* and by this means effec- 
tually decomposed all traces of the aniline group present. But the amount of 
oil heavier than water containing the hydrates of phenyl and cresyl was too small 
to allow of my further examining them. I propose, however, to return to the 
subject at a future time. 
The acid fluid, after decantation from the heavy oil last alluded to, was then 
placed in a retort, and a jet of steam sent through the tubulature to the bottom 
of the liquid; by this means, many non-basic impurities were removed, and 
amongst them a white crystalline solid distilled over with the steam, and which 
eventually proved to be naphthaline. The acid fiuid in the retort, after being 
filtered through pulverized charcoal, to separate resinous matters not volatilized, 
was treated with potash, to liberate the base, which was then separated by a tap 
funnel, and completely dried by digestion with sticks of potash. It is proper to 
*® Srrzman’s Journal 1849; Chem. Gaz., Jan. 1850; Geruarpr, Traité, tome 3™°, p. 83; 
Hormann, Quart. Jour. Chem. Soc. 
