220 Scientific Intelligence. 



4. On the Commencement of the Combination of Hydrogen 

 with Oxygen. — An investigation has been made by Berthelot to 

 determine the precise character of the influence which is exerted 

 upon the combination of oxygen and hydrogen by the walls of 

 the vessel containing the gaseous mixture. The two gases were 

 always mixed in the proportion of two volumes of hydrogen and 

 one of oxygen. It was noted that in presence of dry barium 

 oxide, no combination took place at ordinary temperatures, nor 

 even at 100° or 182°. At 250°, however, 77 per cent of the gas- 

 eous mixture disappeared in five hours, and at 280° the whole or 

 it disappeared in 26 hours. At first, as subsequent experiments 

 showed, the oxygen disappeared more rapidly than the hydrogen, 

 a portion of it uniting with the barium oxide to form peroxide 

 which the hydrogen afterward reduced. Thus, for example, at 

 280° all the oxygen disappeared after five hours, while 16 per 

 cent of the hydrogen remained ; the latter however being slowly 

 absorbed. The action of the barium oxide appears analogous to 

 that of platinum. A similar action was observed with potassium 

 hydroxide, the gases combining slowly at 250° and quite rapidly 

 at 280-300°. In this case the glass is attacked, the manganese 

 which it contains forming alkali manganates. Here also the 

 oxygen disappears more rapidly than the hydrogen, peroxides 

 and manganate being formed. In presence of moisture glass was 

 found to absorb considerable oxygen ; but if the water be in 

 larger proportion, no such absorption was observed. The author 

 regards this intermediate formation of alkali peroxides as taking 

 an important part in the combination of hydrogen and oxygen 

 when heated in glass vessels. — C. H., cxxv, 271-275, August, 1897. 



G. E. B. 



5. On the Different Varieties of Carbon (Amorphous, Graphite, 

 Diamond). — An elaborate investigation has been made by 

 Moissan upon the production, modes of occurrence and general 

 properties of the various forms of carbon. The first of his three 

 papers is devoted to amorphous carbon. Eleven different products 

 were examined, made as follows: (l) by the imperfect combus- 

 tion of petroleum, (2) by the imperfect combustion of acetylene, 

 (3) by the detonation of acetylene with mercuric fulminate, (4), 

 by the action of sulphuric acid on starch, (5) by the action of 

 ferric chloride on anthracene at 180°, (6) by the decomposition of 

 carbon tetriodide at 200°, (7) by the action of light on carbon 

 tetriodide, (8) by the action of a Smithson couple on a solution of 

 carbon protoiodide in carbon disulphide, (9) by the action of zinc 

 filings on carbon tetriodide, (10) by the action of magnesium on a 

 solution of the tetriodide and (11) by the action of boron at a red 

 heat on carbon dioxide. All the specimens of carbon thus pro- 

 duced were amorphous and more or less impure, the complete 

 purification in many cases being very difficult if not impossible, 

 the carbon holding traces of moisture, hydrocarbons and the 

 previously associated elements, iodine, lead, zinc, etc., with great 

 avidity. The most impure samples were those given by methods 



