OF ARTS AND SCIENCES. 357 



001 A ITO = 65° 28' 



ITO A 110 = 50° 55' 

 ITO A 140 = 24° 40' 

 140 A 140 = 79° 45' 



Most of the faces of the crystals were uneven, and the angles printed 

 in heavy type are the only ones which could be measured with 

 accuracy. 



" From these angles the inclination of the axes and the ratio of the 

 ortho diagonal to the cliuo axis may easily be calculated. 



/?=68°38'30" a :b = 1:2.10. 



The crystals vary between the form shown in Fig. 1 and that of Fig. 2. 

 In the second form the clino pinacoid is a characteristic feature which 

 is absent in crystals of the first type, and the forms of both types run 

 out into needles, in one case parallel to the vertical axis, and in the 

 other parallel to the cliuo diagonal." 



The potassium salt is not acted on by a cold solution of potassic per- 

 manganate, but, if heated with it, is oxidized, and we were unable to 

 find any organic matter in the product. 



The following attempts were made to obtain substituted benzoltri- 

 sulphonic acids. The silver salt was made by boiling the chloride 

 with argentic oxide and watei', and to the filtered solution bromine 

 was added in order to make brombenzoltrisulphonic acid by the method 

 of Nolting and Plawski,* which has been proved to be of wide appli- 

 cation to monosulphonic acids by Limpricht.f A heavy precipitate 

 of argentic bromide was formed at once, but the filtrate after being freed 

 from compounds of bromine by evaporation gave a chloride melting at 

 184'*, the melting point of benzoltrisulphochloride. It was analyzed 

 also, as it was barely possible that the brombenzoltrisulphochloride 

 might melt at the same temperature as the non-substituted compound. 



0.2374 grm. of the substance gave 0.2718 grm. of argentic chloride. 



Calculated for Cr,H3(S0.,Cl)3. Found. 



Chlorine 28.52 28.32 



The argentic benzoltrisulphonate, therefore, is affected by bromine 

 in an entirely different way from the monosulphonates. The filtrate 



* Ber. (]. oil. G., 1875, p. 819. t Ann. Cliem., clxxxvi. 134. 



