60 Scientific Intelligence. 



platinocyanide, and their destructive action upon the skin. He 

 mentions two exothermic reactions that have not been previously 

 noticed : the conversion of white phosphorus into the red modi- 

 fication, and the reduction of mercuric chloride to mercurous 

 chloride in the presence of oxalic acid in solution. He mentions 

 finally the interesting fact, recently observed in his laboratory, 

 that seeds exposed to radium rays for a long time before planting- 

 do not germinate. This action is slow, for little effect is noticed 

 after 24 hours, but it is effective after a week or more. — Comptes 

 Mendus, cxxxiii, 709. h. l. w. 



2. The Preparation of Nitrogen from Ammonium Nitrate. — 

 In attempting to prepare nitrous oxide, N 2 0, by the decomposi- 

 tion of ammonium nitrate, the plan of heating this salt with 

 a high-boiling solvent suggested itself to J. Mai. Upon using 

 glycerine for this purpose (50g. glycerine with 25g. ammonium 

 nitrate), and heating to 190°, a gas began to be given off, and 

 this continued without further heating until the temperature fell 

 to 150°. After this a regular stream of gas could be^ obtained by 

 heating to 160° or 170°. It was found that the addition of a few 

 drops of concentrated sulphuric acid to the original mixture 

 lowered the temperature at which the gas came off at first. 

 Upon examining the gas it was found to be nearly pure nitrogen 

 instead of the expected nitrous oxide, and it was shown that 

 oxidation of the glycerine to glyceric acid had taken place. It 

 is possible that the method may be useful in preparing nitrogen 

 on the large scale, and it may be expected that the method of 

 oxidizing organic substances will be useful in other cases besides 

 that of glycerine. —Berichte, xxxiv, 3805. h. l. w. 



3. The Atomic Weight of Tellurium. — According to the 

 position of tellurium in the periodic system of the elements its 

 atomic weight should be less than that of iodine, but the most 

 reliable determinations that have been made in the past have 

 given results which indicate an atomic weight somewhat above 

 127, while that of iodine is considered to be 126*85 (oxygen being- 

 taken as 16). Pellini has recently made some new determina- 

 tions of the atomic weight, using tellurium which had been 

 purified by the recrystallization of diphenyl-tellurium-dibromide, 

 and by distilling the elementary substance in a vacuum. The 

 determinations were carried out by converting weighed quantities 

 of tellurium into the dioxide and weighing the latter, and also 

 by the reverse of this operation. Fairly satisfactory agreements 

 were obtained, and the average of the results indicates an atomic 

 weight of 127'6, which is in close accordance with the value 

 found by several other investigators. — Berichte, xxxiv, 3807. 



H. L. W. 



4. Artificial Spinel. — Although this mineral has been pre- 

 pared artificially by several chemists, it is interesting to notice 

 that Dufajj has found a very simple method of forming it 

 by means of the electric furnace. An intimate and well calcined 

 mixture of 200g. of alumina and 10()g. of magnesia is heated in a 



