EXAMINATION OF A NAPHTHA FROM LIME-SOAP. 189 
second portion of acid blackened like the first, and considerable heat was now evolved, 
but less of the viscid matter was formed. The third portion of acid was still consider- 
ably colored, though much less than the preceding portions. Abundant fumes of 
sulphurous acid were now disengaged, and, as a very considerable proportion of the 
hydro-carbon had been destroyed, the treatment with strong acid was here stopped. 
The hydro-carbon was now washed with diluted sulphuric acid, with chlorhydric acid 
(which caused the hydro-carbon to assume a beautiful purple coloration, which was at 
once destroyed on the addition of potash), and with a solution of potash; it was then 
dried by means of sticks of hydrate of potash. By this time the portion of hydro-car- 
bon operated upon, which originally amounted to 125 c. c., was reduced to 65-70 ¢. c. 
On distilling the purified product upon sodium, from a retort connected with War- 
ren’s hot condenser, the temperature of the liquid rose to 102°, and nothing came 
over until the hot condenser had attained a temperature of 94°. When the tempera- 
ture of the retort had reached 108°-112°, that of the hot condenser being 96°, the 
contents of the retort became very black, and torrents of sulphurous acid were 
evolved; the thermometer in the retort then suddenly rose to 140°-145°, and a very 
violent reaction occurred in the retort. Much water was at this time evolved, a por- 
tion of it having condensed upon the upper part of the retort as soon as this had been 
removed from the fire. The water was evidently generated by the decomposition of a 
portion of the liquid contents of the retort. But, in spite of the water and of the 
sulphurous acid already alluded to, a great part of the sodium in the retort remained 
unacted upon. 
From the foregoing it is evident that during the chemical treatment of this hydro- 
carbon a portion of it combines with the elements of sulphuric acid to form a compound 
of high boiling point, and decomposable at the temperature of ebullition. 
The distillate was at first distributed as five fractions of nearly equal size, each repre- 
senting two degrees centigrade, between 102° and 112°; but, on redistilling, the first 
fraction began to boil at 98,° and the last had all come over before the temperature of 
the retort reached 100.2 After the two fractions thus obtained had been twice redis- 
tilled, it was found that nearly all of the hydro-carbon had collected again as a heap at 
98°-99° This product was, however, still highly charged with sulphurous acid gas, 
in spite of the sodium, which had all the while been present; but, on being washed with 
caustic alkali, the odor of sulphurous acid was at once removed. After having been 
dried with hydrate of potash, the product was distilled upon sodium, in an ordinary re- 
tort, from which it came over at 97.8° (corrected). 
On combustion, 0.1464 grm. of the purified hydro-carbon gave 0.1897 grm. water, 
