EXAMINATION OF A NAPHTHA FROM LIME-SOAP. 181 



best first to subject them to a slight chemical treatment before proceeding to deb r- 

 mine their composition. Most of them were consequently treated with a mixture of 

 two volumes of monohydrated sulphuric acid and one vol inn e of water, 1 1nn 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, bitter, solid 

 hydrate of potash, and distilled repeatedly over metallic sodium before b ing inbjeetcd 

 to analysis. In other cases a treatment with undiluted oil of vitriol Mas 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 l«<n 

 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 wal 

 less strongly colored than the preceding, while the fourth, fifth, and sixth portion 

 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 n H n 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 Fastre thermometers, corrected for atmospheric pi 

 sure, and for the upper column of mercury by II. 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 

 higher boiling points. The precipitates produced by the action of sodium upon these products, or probably upon unpuntics con- 

 tained in them, were white and flocculcnt, 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 Schorlcmmcr's hydrides did not thus act upon «*immJo any 

 appreciable extent. But on the contrary exhibited the same deportment with this metal which we hare u 

 witness when operating upon these and other products obtained from petroleum, etc. 



thewe 



been accustomed 



