EXAMINATION OF A NAPHTHA FROM LIME-SOAP. 199 
As a result of this trial, however, we were led to appreciate more clearly the impor- 
tance of conducting the entire series of distillations, from first to last, in a systematic 
and methodical manner, and of avoiding as far as possible interruptions and irregulari- 
_ ties of every kind; for we have observed how easily one might fall into error by pur- 
suing the opposite course. Thus, after the prominent fractions composing the heap 
165°-173°, had been repeatedly redistilled by themselves, and the products had been 
finally set aside as completed, our attention was next directed to the intermediate frac- 
tions lying between the heap in question and that next below, namely, at about 155°, 
which fractions had latterly been untouched, excepting for the purpose of adding to the 
highest among them the most volatile portions of distillate obtained from the selected 
fractions. It will be observed that, by these additions, the last or highest of the outly- 
ing fractions had become quite large, and that the hydro-carbons composing it were 
undoubtedly mixed in proportions very different from those of the old fractions next 
below. On being now repeatedly redistilled, together with the old fractions, the posi- 
tion of this factitious heap gradually changed to lower degrees of temperature. This 
result was of course to be expected, since the accumulated distillate from the special 
series of fractions would naturally contain much of a comparatively volatile hydro- 
carbon. This change of position was rapid at first, but soon became less marked, and 
after a while a sort of temporary equilibrium was attained at 157°-160°, about which 
point a small heap maintained itself during several distillations. Though this heap 
was evidently still to be regarded as a mixture, both in view of its previous history and 
of the fact that it continued all the while to give up considerable quantities of its ma- 
terial at each successive distillation, it was nevertheless thought best to ascertain some- 
thing concerning its composition, rather than to continue the process of distillation 
until the heap should be completely destroyed. The propriety of analyzing the com- 
pound was, moreover, especially indicated, since there was no apparent improbability 
that a hydride, homologous with those already described, might be found at 158°-159°. 
The heap in question was consequently treated with diluted sulphuric acid, precisely 
as has been described under pelargonene, and again distilled several times through a hot 
condenser: As before, it soon fell into.a condition of equilibrium,—a long flat heap, 
rising gently to a decided summit at 158°-—159°, being constantly obtained. The size of 
the fractions near the summit remained almost absolutely the same during any two or 
three distillations, although considerable quantities of the fraction 150°-151° and of 
residue at 161° were taken off at each successive distillation, and the general behavior 
of the heap indicated that it was still a mixture. 
On combustion, 0.1195 grm. of the purified hydro-carbon gave 0.1348 grm. water and 
