EXAMINATION OF A NAPHTHA FROM LIME-SOAP. 203 
Temperature of the balance, . «© wwe LO 
“ “ — oil-bath, A ae we ks et ee te 248° 
Excess of weight of balloon, . ©. . 2. eee 0.5853 orm. 
Capacity of the balloon, . > 1B ca ee ce e. a ae 217 cc. 
Airremainingin “ . . .  . ee ew 2 @ Occ 
Height of barometer, . . . . . . ee 1) BL he 769,amm. at 25° 
Density of vapor found, . ‘ : : “ ‘ : ‘ es . 5.7814 
Theoretical (Cos Hes), 
oa ce 5.8092 
Its sp. gr. was found to be 0.8361 at 0°. 
We suppose this body to be that member of the C, H, series which boils at 215°, 
but contaminated with some less highly hydrogenized substance. That this contami- 
nating substance is naphthalin we entertain but little doubt, since we have encoun- 
tered a case almost precisely similar to this when studying the hydro-carbons from 
Rangoon petroleum, and in that instance were fortunate enough to crystallize out from 
the hydro-carbon, which corresponds to the one now under consideration, so much 
naphthalin, that we were able to prove its identity by an analysis and by the examina- 
tion of its properties. In the case in hand, however, we could obtain no deposit of 
napthalin on cooling the fractions 202°-203° and 204°-205° in a mixture of ice and 
salt. It may here be stated that no crystals of any kind separated from any of the 
products which have been described above, although all of these were maintained 
during several days at temperatures below 0°. 
Mention has already been made, when specially treating of each of these bodies, of 
the fact that the hydro-carbons boiling at 175°, 195°, and 215° do not readily collect 
in abrupt heaps at a single fraction, but remain dispersed in nearly equal quantities 
through a range of several degrees. This comparative flatness of the heaps of high 
boiling points is in striking contrast with the clearly defined summits of the bodies which 
boil at low temperatures, that is, below 140°. The constituents of Pennsylvanian 
and of Rangoon petroleum, which boil at 175°, 195°, and 215°, exhibit the same 
characteristic flatness ;-which fact, so far as it goes, would tend to indicate their identity 
with the corresponding bodies from the lime-soap naphtha. In the same way it may 
be counted as one item of difference in distinguishing the upper from the lower series 
of the formula C, H,. The tendency of these hydro-carbons to form flat heaps un- 
doubtedly explains one part of the difficulty of removing them from isocumole and 
xylole, to which allusion has already been made. 
‘Tt has occurred to us that it is not altogether unlikely that the flatness of the heaps 
at these comparatively high temperatures may be occasioned by the partial decomposi- 
tion, during distillation, of the hydro-carbons of which the heaps are composed ; if such 
