OP ARTS AND SCIENCES. 99 



Like the isomeric ortho and rneta bodies, the para nitrobenzoic 

 anhydride is an exceedingly difficult substance to burn. It is but 

 slightly soluble in alcohol, ether, benzol and carbon disulphide in 

 the cold, readily however on warming. In ligroine and water it 

 is insoluble. Continued boiling with water converts it into the 

 acid. Alkalies produce the same effect, slowly in the cold, more 

 rapidl} r on heating. 



As in the case of the other nitro-anhydrides the phosphoric resi- 

 due gave, on extraction with absolute alcohol, the para nitrobenzoic 

 ethyl ester. This may be more readily obtained by boiling the 

 anhydride with phosphorpentoxide in absolute alcohol solution. 



It is proposed to extend the study of this phosphorpentoxide re- 

 action to other substituted benzoic acids. 



