EXAMINATION OF A NAPHTHA FR<»M LIME-SOAP. 199 



. As a result of this trial, however, we were led to appreciate raoi clearly the impor- 

 tance of conducting the entire scries of distillation-, from first to last, in a systematic, 

 and methodical manner, and of avoiding as far as possible interruption and irregulari- 

 ties of every kind ; for we have observed how isily one might fall into error by pur- 

 suing the opposite course. Thus, after the prominent fractions composing (lie 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 156°, 

 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 liydro-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°-1G0°, about which 

 point a small heap maintained itself during several distillations. Though this heap 



A ^sV 



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 proce s 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 imp. Lability 

 that a hydride, homologous with those already described, might be found at 168°-159°. 

 The heap in question was consequently treated with diluted sulphuric acid, pr-« i cly 

 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°-lol° 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, 0.1105 grm. of the purified hydro-carbon gave 0.1348 grm. water „nd 









