ON THE BALSAM OF TOLU. 
119 
boiling point of protonitrobenzene is 446° F.) Cinnamic 
acid, when mixed with concentrated and cold caustic soda, 
and exposed to a current of chlorine, becomes transformed 
into chlorocinnamic acid, Ci«(H^ CI) 0"^. However, if the 
temperature is high and the reaction violent, the chlorinated 
oil noticed by Stenhouse is disengaged, and chlorobenzoic 
acid formed. These two acids resemble each other con- 
siderably, but the latter is more soluble in water and alco- 
hol, and the salts crystallize more readily. It is also 
obtained from benzoic acid, caustic soda and chlorine. 
Cinnamic acid, when treated with concentrated nitric acid, 
is at first transformed into nitrocinnamic acid, then into 
benzoic acid, and finally into nitrobenzoic acid. 
Cinnamic and benzoic ethers also become transformed 
but with more difficulty, into nitrocinnamic and nitroben- 
zoic ethers. A great portion of the ether is almost always 
decomposed and the acids set free. Nitrobenzoic aether is 
solid, colourless, and of an aromatic taste and odour. It 
crystallizes in beautiful laminae, belonging to the right pris- 
matic system. Its fusing point is 116° F., and its boiling 
point 564°. It is easily obtained by^subiecting an alcoholic 
solution of nhrobenzoic acid lo a current of muriatic acid. 
Its formula is C''{H^ NO^ )0' = CiW NO^. 
Nitrocinnamic acid, dissolved in an alcoholic solution of 
sulphuret of ammonium, is reduced with the aid of a slight 
elevation of temperature. Sulphur is deposited, and two 
distinct matters are formed, one of which, of a yellow 
madder colour, belongs to the class of resins, and the second 
to the class of alkaloids. The latter is solid, colourless, 
crystallizable in warts, insoluble in water, soluble in alcohol 
and ether, and forms difficultly crystallizable salts. 
Resin a. C^^H^ 0«.— This is brown, translucid, brittle 
when cold, and shining; its powder agglomerates at 59°, 
and fuses completely at 140° F. Concentrated sulphuric 
acid colours it ])urple. When dissolved in caustic potash 
and exposed to the air, it easily becomes oxidised and 
