410 Scientific Intelligence. 



perature absolutely, over a wider thermal range and with a 

 degree of precision and convenience nnapproached by any 

 other known method. 



The present method lends itself easily for the study of disso- 

 ciation phenomena in gases. I hope to be able to show that in 

 the case of imbedded capillaries, the method may be used for 

 the high temperature study of vapor tensions and phenomena 

 near the critical temperature. From such points of view I am 

 justified in believing that the favorable character of my experi- 

 ments introduces a new instrument of pyro chemic research ; 

 an instrument which in addition to the special work to which 

 it may be applied, always subserves the purpose of a pyrometer, 

 and which is particularly available for the coordination of 

 values within a field of high temperature where absolute data 

 are either isolated or wanting. 

 Laboratory U. S. G. S., Washington, D. C. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On the Boiling-point and molecular formula of Stannous 

 chloride. — Biltz and Victor Meter have determined the boiling- 

 point of stannous chloride, the temperatures being estimated by 

 the air thermometer. The first series of experiments gave the 

 value 604*5°, the second series 607 - 7°; the mean being 606*1°. 

 Since this substance is easily procured and is non-volatile, it may 

 serve a useful purpose for vapor density determinations, for which 

 we now have sulphur, boiling at 448° and phosphorus sulphide 

 boiling at 518°. Experiments on the vapor density of stannous 

 chloride show that this constant lessens very slowly with rise of 

 temperature. But they do not confirm the formula Sn 2 Cl 4 , origin- 

 ally given by V. and C. Meyer. The results obtained are con- 

 siderably greater than the formula SnCl 2 requires, but the authors 

 have not obtained a constant value corresponding to the doubled 

 formula. The details of the method will be given shortly. — Ber. 

 JBerl. Chem. Ges., xxi, 22, Jan. 1888. g. f. b. 



2. On the occurrence of Germanium in Ewxenite. — Kruss has 

 discovered the existence of germanium in the acid oxides obtained 

 from euxenite. The mixed oxides were boiled with hydrogen 

 chloride to extract the iron, washed and digested for eight days 

 with ammonium sulphide in a closed vessel. Though all sulphides 

 soluble in ammonium sulphide must have been thus taken up, 

 analysis showed no arsenic, antimony, tin, molybdenum, tungsten, 

 etc. in the solution ; and yet on evaporation and ignition, the 

 solution left a fixed white residue, soluble in ammonium sulphide. 

 The white sulphide obtained by Winkler's method mixed with 

 sulphur, was heated in a current of carbon dioxide and left a 



