6 Dr. Stenhouse on the Products of the Distillation 



improper to employ a solution of a caustic alkali to remove 

 the benzoic acid, as such a proceeding would certainly destroy 

 a large proportion of the neutral compound. The crystals 

 were next collected on a filter and washed with cold water till 

 every trace of alkali was removed. They were then dissolved 

 either in hot alcohol or in aether, in both of which liquids they 

 are exceedingly soluble, and were purified by repeated cry- 

 stallizations. They crystallize out of aether in large four-sided 

 oblique rhombic prisms. The crystals are hard and brittle, 

 and grate between the teeth like sugar. They have a faint 

 aromatic smell, somewhat resembling that of the geranium, 

 but when heated approaching that of lemons. When slowly 

 deposited from an aethereal solution, the crystals may be rea- 

 dily obtained an inch in length. Their melting-point is 70° C. 

 After they had been kept melted for some time, to drive off 

 any adhering aether, they were dried in vacuo over sulphuric 

 acid and subjected to analysis. 



I. 0*3508 grm. substance burned with chromate of lead, 

 gave 1'024<2 cai'bonic acid and 0'161 water. 



II. 0*3902 gave 1*1437 carbonic acid and 0'182 water. 



1313-39 100*00 100*00 100*00 



It is evident from these analyses that this compound con- 

 tains only one atom of oxygen less than benzoic acid, the for- 

 mula of which is Cj4 Hg Og, and consequently it is isomeric 

 with benzile. It differs very essentially from benzile, however, 

 for when it is heated with solid potash it is immediately con- 

 verted with evolution of hydrogen into benzoate of potash ; 

 while benzile, when similarly treated, yields, as is well known, 

 benzilate of that alkali. When treated with an alcoholic so- 

 lution of potash, it quickly forms benzoate of potash without 

 any change of colour, while at the same time a little benzoic 

 aether is also produced. When it is boiled with an aqueous 

 solution of potash or soda, it is also converted into benzoic 

 acid, though more slowly ; and a portion of the compound is 

 apt to distil over undecomposed. A quantity of the acid ob- 

 tained by decomposing the neutral compound with an alkali 

 in the way just described was purified by repeated crystalliza- 

 tions and subjected to analysis. 



0*3807 grm. substance, dried at 100° C, gave 0*9575 car- 

 bonic acid and 0*1698 water. 



