396 Intelligence and Miscellaneous Articles. 



A concentrated solution of clavyum chloride gives, with potassic 

 sulphocyanide, a red precipitate which, slowly cooled, produces 

 large red crystals. I£ the same precipitate is calcined, the davyum 

 sulphocyanide takes the form of a black powder. These reactions 

 show that this salt is allotropic. 



The chloride is very soluble in water, alcohol, and ether ; but 

 the crystals of this salt are not deliquescent. Calcined, the salt 

 gives as residue the monoxide. The chloride of davyum forms 

 double salts with the chlorides of potassium and ammonium ; they 

 are insoluble in water, and highly soluble in absolute alcohol. The 

 double salt of sodium and davjaim is almost insoluble in water and 

 iu alcohol ; this reaction is characteristic, because several sodic 

 salts of the platinum group are highly soluble in w^ater. 



This chloride of davyum is the only one that exists, as the 

 second product, containing more chlorine, decomposes during the 

 evaporation of the solution, liberating chlorine. 



I have made some new researches upon the density of cast 

 davyum ; three experiments gave the following numbers — 9*388, 

 9-387, 9-392 at 24° C. 



These results agree very closely with those of my first trials : 

 the density given in my first Note was 9*385 at 25°. 



M. Alexejeff, engineer, has undertaken the determination of the 

 equivalent of davyum ; but as the quantity of the metal which I 

 possess is very trifling, accurate results are very difiicult to obtain. 

 Some preliminary experiments have shown that the equivalent is 

 above 100, and probably not far from 150-154. 



An additional quantity of platiniferous sand which will be placed 

 at our disposal will give a sufficient supply of the new metal for 

 fresh experiments ; we expect to have, in a little time, about 1-2 

 gramme of davyum. — Coniptes Rendus de VAcademie des Sciences, 

 October 1, 1877, tome Ixxxv. pp. 623, 624. 



THE GAMUT OF LIGHT. BY PLINY EARLE CHASE. 

 In accordance with a suggestion of Dr. Henry Draper, that I 

 should test some of my views by the spectral lines, I have under- 

 taken a preliminary investigation, with the following result. 



In the harmonic progression, -, , -— ,&c., letc=wave- 

 n n -|- f*^ ^ + 2a 



length of Fraunhofer line A, =761*20 millionths of a millimetre; 



n= 1-015, « = -0918, and we find the following accordances : — 



Numerator. Denominators. Quotients. Observed. Kirclihoff. 



761-20 n + a 687*75 687*49B 592*7 



n + 2a 635*07 634*05 783*8 



n+Sa 589-89 589-74Dy 1005-1 



n + 4a 550-72 550-70 1306-6 



n-\-5a 516-42 517*15 1655*6 



n + 6a 486*14 486*52r 2080*0 



n + 7rt 459*22 458*66 2436-5 



n + 8rt 435-12 435-67 2775-7 



n + da 413-43 ? ? 



n + lOa 393-79 393-59 H' H' 



