Chemistry and Physics. 409 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Determination of Carbon in Steel. — The usual method for 

 determining carbon in steel by combustion involves the prelimi- 

 nary solution of the metal in ammonium cupric chloride or some 

 other solvent. This process is a long one, and there is some 

 uncertainty in regard to obtaining all the carbon in the insoluble 

 residue. The fact that it is possible to determine carbon in steel 

 by direct combustion will doubtless be welcomed by all steel- 

 works chemists. Leffler has succeeded in accomplishing this 

 much-desired operation. A porcelain combustion-tube (20 Xl^ 

 inches) containing a few inches of copper oxide is used. 2^ 8 of 

 borings are mixed with 6 s of red lead and transferred to a porce- 

 lain boat (4xf inches). The boat is put into the hot tube after 

 the calcium chloride tube and potash-bulbs have been attached, 

 purified air is passed through, while the part of the tube contain- 

 ing the boat is raised to a very high temperature. This is accom- 

 plished by using an asbestos arch, shaped like a muffle, in place 

 of the usual tiles of the combustion-furnace. The asbestos is 

 perforated with numerous holes for the passage of gas and air, as 

 well as for the products of combustion, and over the part of the 

 tube containing the boat a second, larger asbestos arch is placed 

 for increasing the temperature at that place. With a good hot 

 furnace the combustion is complete in half an hour, even when 

 air only (2£ liters) is passed through. When drawn from the 

 hot tube, the contents of the boat can be easily scraped out with 

 a suitable piece of metal, and the boat may be used over and 

 over again. The use of borings which have passed through a 

 sieve of 20 meshes to the lineal inch is recommended, but, by 

 increasing the period of heating, fragments as large as peas and 

 pieces of sheet steel have been satisfactorily burnt. Leffler gives 

 many results of combustions made by the direct method, which 

 are compared with the old method. These are very satisfactory, 

 with a tendency, as might be expected, for slightly higher results 

 vith the direct process. — Chem. JVeios, lxxxv, J 21. h. l. w. 



2. New Synthesis of Methane. — Marsh-gas, or methane, CH 4 , 

 has been formed by the action of a mixture of carbon bisulphide 

 and hydrogen sulphide upon red-hot metallic copper ; by the 

 ignition of barium formate, the latter having been prepared from 

 potassium formate produced by the slow absorption of carbon 

 monoxide by caustic potash ; by the action of a mixture of car- 

 bon bisulphide and water-vapor on metallic iron ; by the action 

 of hydriodic acid gas upon carbon disulphide ; by the action of 

 hydriodic acid upon phosphonium iodide in a sealed tube at 

 120-140° ; by the action of electric sparks upon a mixture of 

 carbon monoxide and hydrogen ; and by the action of water 

 upon aluminum carbide and other carbides. Sebatier and 



