EXAMINATION OF A NAPHTHA FROM LIME-SOAP. 203 



Temperature of the balance, 25. 



" " oil-bath, . 



Excess of weight of balloon, 



o 



Capacity of the balloon, 

 Air remaining in " 



Height of barometer, 



148° 



0.5853 grm. 

 217 c. c. 



c. c. 



G 9.3mm- at 25° 



Density of vapor found, , 5.7314 



Theoretical (C24H24), 5.8092 



Its sp. gr. was found to be 0.8361 at 0°. 



' We suppose this body to be that member of the C n II n .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 rammita 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 n H tt . 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. 



It 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 



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