EXAMINATION OF A NAPHTHA FROM LIME-SOAP. 181 
best first to subject them to a slight chemical treatment before proceeding to deter- 
mine their composition. Most of them were consequently treated with a mixture of 
two volumes of monohydrated sulphuric acid and one volume of water, then washed 
with a dilute solution of hydrate of potash,—here avoiding agitation which is liable 
to-give rise to emulsions, — then dried over chloride of calcium, or, better, solid 
hydrate of potash, and distilled repeatedly over metallic sodium before being subjected 
to analysis. In other cases a treatment with undiluted oil of vitriol was resorted to 
as will be described further on. 
The diluted acid above mentioned was added to the hydro-carbon, by successive 
small portions, each portion of acid amounting to perhaps one-fiftieth or one hundredth 
of the bulk of the hydro-carbon, the two liquids being violently agitated together dur- 
ing five or ten minutes, and. the acid sediment finally drawn off after having been 
allowed to settle. As a general rule the first portion of acid became very dark colored 
and slightly viscid, although the hydro-carbon did not become colored to any extent; 
the second-and third portions of acid behaved in a similar manner, though each was 
less strongly colored than the preceding, while the fourth, fifth, and sixth portions 
were only slightly colored. Since the hydro-carbon itself usually began to become 
colored on the addition of the fourth or fifth portion of acid, the acid treatment was 
rarely pushed beyond this limit. The caustic potash appeared to exert little or no 
action upon the hydro-carbons, serving only to remove the last traces of the acid em- 
ployed. In practice it was found that while the bodies boiling at 35° and other de- 
grees of temperature, the names of which end in five,-that is, those of the formula 
C,, H, could be obtained in a state of tolerable purity by the treatment just described, 
the members of the other series required further purification before being fit for analy- 
sis, as will appear in the sequel. 
_ Before proceeding to describe in detail the several bodies which we have isolated 
from the lime-soap naphtha it should be remarked that all statements of temperature 
refer,to the uncorrected indications of ordinary thermometers, and make no claim to 
special accuracy, excepting when followed by the word “corrected,” in which event they 
refer to the indications of the best Fastré thermometers, corrected for atmospheric pres- 
sure, and for the upper column of mercury by H. Kopp’s formula. The method of de- 
in order to obtain purity. The more volatile members of this series ceased to act upon sodium much more quickly than those of 
higher boiling points. The precipitates produced by the action of.sodium upon these products, or probably upon impurities con- 
tained in them, were white and flocculent, and closely resembled in appearance hydrate of alumina. It is worthy of remark that 
the heaps composed of members of the benzole series and of Schorlemmer’s hydrides did not thus act upon sodium to any 
appreciable extent. But on the contrary exhibited the same deportment with this metal which we have been accustomed to 
witness when operating upon these and other products obtained from petroleum, etc. 
