Ferric Acid. ggf) 



Several acids of similar composition give crystallizable 

 eethers; the most beautiful is that of benzoenitric acid 

 (C H'^ O, C'^ H« N^ O'). The following crystallize well: 

 picnnnitrate and anisinnitrate of aethyloxide, and the benzoe- 

 nitrate of methyloxide. 



Cinnamic acid may be very easily distinguished from ben- 

 zoic acid by the formation of the cinnamonitric acid. The for- 

 mula is C'^ H'^ N- O', or C H" O' + N- O' - H- O. The 

 uncombined acid is C'^ H'< N- 0\ 



If more than one part of cinnamic acid is added to ei<rht 

 pai'ts of nitric acid, the temperature rises above 60°, and ben- 

 zoenitric and another, as yet unexamined, acid are formed. 

 The crystallized acid (benzoenitric) contains one atom of 

 water, according to Mulder; he calls it " acide nitroben- 

 zique :" benzoiinitric is more applicable. 



Cinnamic acid does not combine with sulphuric acid as 

 benzoic acid does. By distilling cinnamic acid with lime, 

 carbonate of lime and carbon remain behind, and die product 

 is a mixture of several substances ; it smells like benzin, but 

 is fluid under 0°; it perhaps contains some benzin, but is 

 certainly a mixture. The same is the case with the products 

 obtained by passing camphor and oil of cinnamon through a 

 red-hot tube, according to the experiments of H. C. (D^Ar- 

 cet's fluid, which is said to be like benzin, but to boil at 14.0% 

 I could not obtain; the oil procured began to distil at 140°, 

 but the boiling point rose to 2,50°.— H, C.) 



Ferric Acid. 

 M. Fremy has found that if a mixture of the per- 

 oxide of iron and potash, or better one of peroxide of iron 

 and nitre and potash, or also peroxide of potassium be kept 

 for a time at a lively red heat, a brown mass is obtained, 

 which, when treated with water, afibrds a very beautiful violet 

 solution. The combination contained in this solution can 

 likewise be formed in the moist way, by passino- chloiine into 

 a very concentrated solution of potash in which the hydrate 

 of the peroxide of iron is suspended. The combination pre- 

 pared in eitiier way is of a beautiful violet, very soluble in pure 

 water, insoluble in alkaline watei-, in which it forms a brown 

 precipitate, which redissolves in pure water with a purple co- 

 lour. It appears to be less stable than the manganate of 

 potash. Under certain circumstances (for instance, with time 

 in much water), it decomposes at the common temperature 

 into peroxide of iron, which falls to the ground, and into oxy- 

 gen, which esca|)es, while all colour disaj)pears. A tempera- 

 ture of 100° |)roduces the same decomposition instantaneously, 

 Phil, Ma^. S. 3. Vol. 18. No. 118. Mai/ 184'1. 2 B 



