326 Scientific Intelligence. 



react with it. The average result, after all corrections had been 

 made, was 55*870, a remarkably close agreement with the result 

 of the other method. 



In connection with this work the effect of the earth's magne- 

 tism upon the weight of magnetic substances has been discussed, 

 and it has been shown by experiment to be entirely inappre- 

 ciable. — Zeitschr. An organ. Chem., xxxviii, 232. n. l. w. 



5. Method of Separating Iron and Aluminium. — A method 

 for making this analytical separation by boiling in the presence of 

 an excess of sodium thiosulphate has been suggested by Chancel, 

 but it has not been found satisfactory. Leclere has modified 

 the method by first adding ammonium thiosulphate to the very 

 dilute solution containing a slight excess of sulphuric acid. This 

 reduces the iron to the ferrous condition. Then a large excess of 

 ammonium formate is added, and the aluminium is precipitated 

 by boiling, in the state of basic formate. In drying the precipi- 

 tate it is advisable to treat it with nitric acid, in order to destroy 

 formic acid and prevent the presence of a residue of carbon in 

 the ignited alumina. The iron can be precipitated in the filtrate 

 as sulphide. — Comptes Pendus, cxxxviii, 146. h. l. w. 



6. Phosjyhorescence. — Albert Dahms gives an historical sum- 

 mary of the results of Seebeck and of Becquerel ; and takes up 

 the study of the phenomena discovered by them with the addi- 

 tional aid of photography. A number of interesting photographs 

 accompany the paper. The various substances were exposed to 

 the light of the carbons of an electric arc, and the photographs 

 show carbon bands in the blue portion of the spectrum, and also 

 in some c*ases bands in the extreme infra-red. The author shows 

 that the phenomena are conditioned not only by the relative veloci- 

 ties of the rays, but also by the amount of energy contributed to 

 the phosphorescent substances, and also by the inherent energy 

 of such substances. — Ann. der Physik, No. 3, 1904, pp. 425-463. 



J. T. 



7. Preliminary Measurements of the Short Wave lengths dis- 

 covered by Schumann. — For the past few years Dr. Theodore 

 Lyman has been engaged in the Jefferson Physical Laboratory in 

 an attempt to measure the short wave lengths discovered by Dr. 

 Victor Schumann ; but it is only recently that this attempt has 

 proved successful. 



Working in an atmosphere of hydrogen with a concave grating 

 ruled upon speculum metal, an end-on tube filled with hydrogen 

 gives numerous lines below the aluminum group at 1854. The 

 shortest wave length so far observed has a value 1178 Angstrom 

 units. The limit of error is two units. 



It is interesting to note that, contrary to expectation, speculum 

 metal is able to reflect these very short wave lengths to a consider- 

 able degree. This is merely a preliminary notice. The author has 

 in preparation a complete list of these new wave lengths ; and 

 he has good hopes of still further extending the spectrum. It is 



