Chemical Scienoet^yM. 429 



6nce of Us salts from the benzoates, and by its composition iixcjiudipg 

 azote. It fuses by heat, then is decomposed and becomes blacji,,^ 

 crystalline sublimate rises, an odour of bitter almoi>ds is perceiv^». 

 and much charcoal is left. Bein^ mixed with four times its weight 

 of hydrate of lime and heated, much ammonia is disengaged. 

 . I. Being obtained from the urine of the horse principally, it l}&^ 

 been distinguished by the term hippuric acid. Sulphuric acjcj, 

 lieated to 248° F. dissolves it without change, water precipitates it,;, 

 a higher heat enables the acid to decompose it, and ultimately whit^^j 

 crystals sublime. It dissolves also in nitric acid, and by heat ji^. 

 then decomposed. It is soluble in hot muriatic acid, but crystaJl-j. 

 lizes out upon cooling. Aqueous solution of chlorine does not^i^ 

 upon it, biit boiling with much chloride of lime decompo^^j^lf 

 entirely. ' ' . ipfm 



When burnt very carefully by means of oxide of copper, it gave^j 

 mixture of carbonic acid and azote in the proportions of 100 to 5. 

 This result appearing important, was confirmed by another mode of 

 investii»ution, namely, by burning, not the acid, but its ammoniacal 

 salt, by means of peroxide of copper, and observing the relation of 

 the azote to the carbonic acid. The oxalate of ammonia burnt ia 

 this way yields 1 volume of azote and 2 of carbonic acid, the latter^ 

 indicating so many volumes, i. e., 2 of carbon. The acid hippurate 

 of ammonia so burnt gave 2 of azote and 27 of carbonic acid, con- 

 firming the result above. By other analytical processes the quan- 

 tity of water given by 0.300 parts of the acid when burnt, was 

 foimd to be 0.180, and from these and other data the following com^ 

 position was made out : 



,iL^ Azote .4 '.<., i ,046 or, theoretically, 14 1 atom. .,, 



»fff Carbon K^-vf. t.«.393 . . 120 20 atoms. ,^., 



« r Hydrogfeo 'i f ^o.OSl . • 10 10,* y.^^^ ^mts4 



Oxygen .><4l:< /"^155 . • 48 6.'; Si.J Mfi.tif 



Vf«^,?i\^m"^vV.vv,rc- .625 192 



I'tFhe mean result of experiments on its atomic weight was 197. 

 !tnthe hippurate of lead, 100 parts of the acid combine with 55.31 

 oxide of lead, and the crystallized salt contains besides 25.64 of 

 water. The hippuric acid, when crystallized, is anhydrous (an4 

 requires 60O parts of water at 32° for its solution. , . ..^^ 



Hippuric acid easily dissolves most of the metallic oxides. The 

 soluble compounds precipitate solutions of iron of a rusty colour, and 

 the nitrates of silver and protoxide of mercury, in a white Hocculent 

 state. The neutral ammoniacal salt crystallizes with difficulty, 

 the acid salt easily. These, when heated, evolve ammonia, and 

 leave ])rincipally hippuric acid. The hippurates of potassa, soda, 

 and magnesia, are very soluble and difficultly crystallizable. The 

 hippurates of baryta and strontia are soluble and crystallizable. The 

 sub-salt of baryta has peculiar properties. The salt of lime crys- 

 tallizes in rhomboidal prisms, &c., which are anhydrous : they dis- 

 solve* in 18 parts cold water, and 6 parts of boiling water; it 



