Intelligence and Miscellaneous Articles. 



315 



forces up to 12,500 C.Gr.S. (and probably up to much higher 

 values). This was proved by direct measurement on H 2 0, and 

 solutions of FeCl 3 and MuCl 2 within the range of experimental 

 errors. 



A solution of any paramagnetic salt in a diamagnetic liquid may 

 be brought to a certain concentration at which it is magnetically 

 11 inactive n in a given field. By the qualitative test alluded to it 

 was then found inactive in any other field ; from this fact an indi- 

 rect verification of the absolute constancy of the susceptibility of 

 both the liquid and the salt in solution is easily deduced. Various 

 salts and oxygen were thus tried, all with the same result. 



The properties of solutions were further investigated at some 

 length, specially at the concentrations for which they proved either 

 optically or magnetically inactive ; the general result being a con- 

 firmation of the assumption usually made, viz. that the action of 

 solvent and dissolved salt is algebraically superposed. 



So-called amalgam of iron seems to behave differently from 

 simple liquids ; its magnetization appears to reach a maximum like 

 that of massive iron. This result was calculated from some of 

 Quincke's data by a formula deduced on the most general assump- 

 tion of varying susceptibility. The reason of this probably is 

 that the amalgam is neither a chemical compound nor a real solu- 

 tion, but rather an emulsion of exceedingly small particles of iron 

 in the mercury. However, this question can hardly be decided 

 without further experiment. 



The susceptibility of oxygen (at 1 atmosphere of pressure) rela- 

 tively to that of water was found to be Ol-i. at 15°. It was found 

 to decrease with temperature much more rapidly than the density, 

 a result published somewhat earlier by Quincke*. 



The temperature-coefficient of the susceptibility of water was 

 found to be a decrease of 0*25 per cent, per degree. 



Besides the qualitative a erification of the sign of the susceptibility 

 and of Yerdet's constant for the substances most characteristic in 

 this respect, absolute determinations were made of the suscepti- 

 bilities of a few standard substances. The values at temperature 

 15° are contained in the following table, the susceptibility of a 

 vacuum being of course taken as zero (its permeability =1). 



Substance. 



Density. 



j Susceptibility. 



Water 



09992 



0-7963 



07250 



1-2692 



0-00135 



0-00123 



-0837. 10 " 6 

 ! -0-694 „ 

 -0-642 „ 

 -0-816 „ 

 +0-117 M 

 1 +0024 „ 



Alcohol 



Ether 



Bisulphide of carbon 



Oxygen; 1 atmosphere ... 

 Air; 1 atmosphere 





* Wied. Ann. vol. xxxiv. p. 442 (1888). 



