66 REPORT— 1873. 



citraconamide produced. However, citraconic anhydride treated with sulpho- 

 carbamide yields the citraconsulpho-carbaminic acid 



/CO— NH— CO— NH, 

 C3H, 

 \COOII 



This body has similar properties to those of the foregoing acids. It fuses at 

 222-223° C. No such combination could be obtained between lactide and urea, or 

 between lactide and sulphocarbamide. In the first case lactamide and carbonic 

 acid were produced ; in the second, lactamide and oxysulphide of carbon. 



On Horn Silver. By "W. Chandler Roberts, F.C.S. 



On the Constitution of some Silicates. By Professor Schafaeik, Prague. 



On Artificial Magnetite. By John Spillee, F.C.S. 



The object of this communication was to point out an error in the statement of 

 a chemical reaction occurring in several standard works of reference, and, in the 

 second place, to indicate the formation of cry.^tallized magnetic oxide of iron 

 (magnetite) in the ordinary process of manufacturing aniline from nitrobenzol by 

 the reducing action of metallic iron. 



Reference was made to Reimann's ' Aniline and its Derivatives,' and to Wagner's 

 ' Chemical Technology,' where the action of iron upon nitrobenzol in the presence 

 of acid (B^champ's process) is stated to give ferric oxide or a " hydrated oxide 

 of iron." The author pointed to the fact that the ordinary residual product in this 

 operation was blade, and could be so far purified by washing and elutriation from 

 the excess of iron usually remaining in admixture as to give a fine black pigment, 

 which appeared under the microscope as minute octahedra, and was strongly 

 magnetic. Chemical analysis showed this to consist almost entirely of magnetic 

 oxide of iron, with such impurities as were inherent to the process or previously 

 existed in the cast iron. The physical properties of this form of oxide were 

 fiu"ther described, and its analogy to the native varieties of magnetic ore (Cornish 

 and Dannemora) shown by the following analysis of the substance dried at 

 110° C.:- o J 



Fen-ic oxide 67-00 



Ferrous oxide 30'05 



Graphite 1-23 



Silica -78 



Phosphoric acid -02 



Sulpliur and manganese traces 



99-G8 



Metallic iron (total) 70-27 



On a form of Gas-generator. By C. J. Woodward, B.Sc. 



What are required in a gas-generator are a ready means of bringing the acid 

 into contact with the zinc, marble, &-c., and, what is of even greater importance, a 

 ready means of removing it when the supply of gas is no longer wanted. The 

 generator devised by Dobcreiner is theoretically perfect ; but, owing to slight leakage, 

 it win not remain in action for any length of time. 



Two forms of generator were described. The first consists of a stoneware vessel 

 somewhat similar to a Woulfe's bottle. To one of the tubulures is fastened a glass 

 cylinder containing the zinc, marble, &c. ; to the other tubulure is attached a tube 

 through which a plug of wood passes loosely. To bring the apparatus into action 



