Chemical Notices : — M. Schmidt on some New Acids* 139 



The same analogy which led me to suppose that dioptase had 

 two optical axes, has also reference to the tungstates of lime, 

 Pyramidites hystaticus and Pyramidites macrotypicus (B. M. 

 pp. 266 to 260); and I most certainly believe that the asymme- 

 trical condition of their planes will be discovered ; and if trans- 

 parent crystals can be obtained, they will be found to have two 

 optical axes. 



The translator has had a letter from Professor Breithaupt, 

 wishing him to add the following remarks to this paper. 



" The tungstates of lime show two optical axes beautifully. I 

 have measured Hessonite and found the variation to be 12 mi- 

 nutes, while in almandine and melanite it was only 6 minutes. 



" Further, mellite or honeystone shows two optical axes, and 

 is also very decidedly asymmetrical in the same way as idocrase, 

 though with a greater difference in its augles. 



" Finally, I have found a calc-spar or carbonate of lime with 

 one optical axis and of asymmetrical form." 



XV. Chemical Notices from Foreign Journals, By E. Atkin- 

 son, Ph.D., F. C.S.j Teacher of Physical Science in Cheltenham 

 College. 



[Continued from p. 50. J 



ACCORDING to Laurent, sulphanilidic acid is obtained by 

 the reducing action of sulphide of ammonium on nitrosul- 

 phophenylic acid ; and this acid is identical with the acid obtained 

 by the action of anhydrous sulphuric acid on aniline. Kolbe is of 

 opinion, on the contrary, that they are only isomeric, and that 

 the same relation obtains between them as between the isomeric 

 carbanilic and benzamic acids. Thus : 



H0 ' C12 NH2} C2 ° 2 '° H0 ' ( C12 H} N ) C202 > a 



Amidobenzoic acid Carbanilic acid, 



(benzamic acid). 



H0 ' C ' 2 NK*} S * ° 4 ' ° H0 ' (° 2 H 5 } N ) S * °*» °- 



Amidophenylsulphuric acid. Sulphanilic acid. 



These formula? show that amidobenzoic acid and amidosulpho- 

 phenylic acids are respectively derived from carbonic acid, and 

 sulphuric acid by the substitution of an atom of oxygen by the 



group amidized phenyle, t^tj2 f ; while in carbanilic and 



sulphanilic acids this atom of oxygen is replaced by phenylamide, 



C 12 H 5 1 . 



jj r N, that is, amide in which an atom of hydrogen is re- 

 placed by phenyle. 



L2 



