120 Dr. A. W. Hofman on the Organic Bases 



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the retort. When I left the yellow oil for some days in con- 

 tact with an equal weight of fused hydrate of potash in a closed 

 glass cylinder, there was formed at the bottom of the vessel 

 an aqueous solution of this alkali. The anhydrous oil was 

 then carefully removed with a dry pipette and quickly distilled 

 in a current of hydrogen gas, dried by means of sulphuric 

 acid. I received the distillate in three different portions. The 

 jirst might still have contained traces of water and ammonia, 

 the third was feebly coloured yellow, and its last portions pos- 

 sessed in a less degi'ee the property of colouring with chloride 

 of lime. The second portion was a beautiful, colourless iri- 

 descent liquid. In such cases, uniformity in the results of se- 

 veral analyses can alone satisfy us respecting the purity of a 

 substance, therefore I burned the first portion of my distillate 

 with oxide of copper, and then distilled the remaining part. 

 A small portion, which was received at the end of the distil- 

 lation, was also analysed with oxide of copper. The results 

 of the two analyses agreed perfectly ; to this I shall advert 

 hereafter. The middle or second portion of oil that passed 

 over in the second rectification I considered to be pure cyanol. 

 The portion that passed over last in the preparation of the 

 crude bases, and which, as was remarked, did not produce a 

 blue reaction with chloride of lime, was dehydrated and distilled 

 twice in a stream of dry hydrogen gas. The middle portion 

 of the product of distillation was a liquid smelling not very 

 unpleasantly, possessing a slight yellow hue, and of an extra- 

 ordinary refractive power. I burned it with oxide of copper; 

 the results obtained agreed with the results of further analyses, 

 which were made with different portions of this oil many times 

 redistilled. This slightly coloured liquid may therefore be 

 regarded as pure leucol. 



The above-described method depends upon the unequal vo- 

 latility of the two bases; from the same cause very varying 

 quantities of each oil are obtained when different portions of 

 the heavy coal-gas naphtha are employed. Dr. Fabian von 

 Feilitzsch procured, by the treatment of an oil which was ob- 

 tained from the same source as mine, pure leucol, unmixed with 

 the slightest trace of cyanol. A considerable quantity of an- 

 thracene (paranaphthaline) was deposited from this oil, which 

 proves that it must have belonged to the last period of distil- 

 lation. I repeated and investigated this experiment with a 

 large quantity of coal-gas naphtha which Dr. Sell had distilled. 

 This oil, which on cooling partly consolidated into naphtha- 

 line, contained only leucol. In the same way I have examined 

 the oil which passes over after the evolution of the hydrocar- 

 bons. This was not free from leucol, but it contained an in- 



