200 EXAMINATION OF A NAPHTHA FROM LIME-SOAP. 
0.3832 grm. carbonic acid (I.). Another portion, not weighed, gave 0,18 grm. water and 
0.5138 grm. carbonic acid (IL). 
Found. 
I. I. 
Carbon 87.46 87.51 
Hydrogen 12.47 12.49 
99.93 100.00 
From these results we derive the formula C,, Hy;4. It appears, then, that this 
spurious heap is composed in great part of a member of the benzole series, — undoubt- 
edly of the one which boils at 170° (isocumole) ; indeed, the formula last given is much 
nearer that of isocumole than the one previously derived from an analysis of the frac- 
tion 165°-166°. During the redistillation of the intermediary fractions the volatile 
matter, which, as fast as it was eliminated from the products 165°-173°, had been 
heaped up at the upper extremity of the intermediary series [namely, at 163°-164°], 
gradually came forward towards its own proper place at 153°, or thereabouts, and in 
so doing dragged along with it a quantity of the isocumole properly belonging at 170°, 
until a point was reached at which the tendency of the isocumole to go back nearly 
balanced the power of the 153° body to go forward, and at this point a temporary heap 
of course arose. At the moment of the analysis, this heap had been operated upon so 
long that the isocumole was largely in excess; but if an analysis had been made of the 
heap as it existed a week earlier, a different result would undoubtedly have been ob- 
tained. 
Such temporary adjustments, or, as it were, balancings of the opposing forces exerted 
by two bodies of different degrees of volatility, are noticed not unfrequently in the 
course of ‘the earlier series of distillations of a mixture of crude hydro-carbons. Soon 
after definite heaps first begin to appear, there will be seen for a time, at points about 
midway between the real, permanent heaps, small temporary elevations, which subse- 
quently disappear again as the distillation progresses. But as at this stage of opera- 
tions all of the fractions are far from possessing constant boiling points, no question as 
to the lack of individuality of these half-way heaps can well arise. It is probable that 
the danger of mistaking a counterfeit for a real heap can only occur by virtue of some 
such cause as in the instance above cited, or where one of the components of a mixture 
of two bodies is in large excess as compared with the other. Perhaps the substance 
encountered by Pelouze and Cahours* at 136°-138°, and described by them as hydride 
of pelargyl=C,g Hy, may have been nothing more than a spurious heap, such as 
* Bulletin de la Société Chimique de Paris, 1863, pp. 235, 238. 
