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 LII. Intelligence and Miscellaneous Articles. 



CONTRIBUTIONS TOWARDS THE KNOWLEDGE OF FLUORESCENT 

 BODIES. BYG. WERTHER. 



IN the following experiments a ray of light was thrown, by means 

 of a heliostat, upon a prism provided with a lens, and the portion of 

 the spectrum from the red to the violet was shut off. The substances 

 to be examined should in this arrangement be held only in the violet 

 and opake portion of the spectrum. It appeared, and indeed this is 

 characteristic of fluorescent bodies, that all the violet was extin- 

 guished, and instead of this a yellowish or bluish-green Hght of 

 greater or less intensity made its appearance. In the other parts of 

 the spectrum these bodies exhibited the usual prismatic colours. 

 The greater or less extent of the fluorescent part of the spectrum 

 was always compared with some sulphate of quinine spread upon 

 paper which was stretched over a glass plate." Some of the sub- 

 stances which are fluorescent in the solid form were also dissolved 

 and laid upon paper. Protocyanide of potassium and platinum laid 

 on to a suflicient thickness, appeared, with regard to the extent and 

 distinctness of its projection of Fraunhofer's lines, as good as sul- 

 phate of quinine. Acetate of uranium and soda did not show fluor- 

 escence until its concentrated solution had been appHed several times. 

 Its solution also did not exhibit the epipoHzation (the bluish lustre) 

 presented by solution of sulphate of quinine. Solution of protocy- 

 anide of potassium and platinum also does not exhibit this property 

 when greatly diluted. The salts examined were, — 



Compounds. In the violet. Behind the violet. 



U O , PO , 5HO 1 Strongly yellowish-ffi-een. Fluorescent greenish-yell. 



U203, A.S05, 5H0 J ^^ ^ ^ 



(2U-03-|-HO)P05-f8IIO.. .Bluish-green. Fluorescent greenish-yell. 



(21)2 03+HO)P05+6HO. ..Very slight greenish-yellow. Slight yellowish-green. 

 (2U2 03+HO)P05-f 3H0... No result. 



(2U2 03-(- H0)P05 Strongly yellowish-green. Slight greenish-yellow. 



(2U203+HO)AsO^+8HOU^^^^^,j^_ Slight greenish-yellow. 



(2U2 03+HO)AsO*-f6HOJ ^ 



(CaOH-2U=03)PO^+8HO 1 g^^^^ ^^^.^^^^^ Strong yellowish-green. 



The same, as lime-uranite. J 



(CuO+2U2 03)P0=+8HO1 N^^^^^l, 



The same, as chalcolite. J 



(CuO-f2U2 03)As05+8HO. No result. 



KOA-|-2(U-03A)-H2HO ...No result. Slight yellowish-green. 



NaOA+2(U2 03A) Bluish-green. Strong yellowish-green. 



(U2 03)2, P0S-1-(U2 03)3, P05 1 



2(2U3 03, P05)-|-NaO, U-03-f3HO I No result. 



(NaO-|-2U2 03), AsOHSHO J 



U-03, X05+6HO Strong yellowish-green. Strong greenish-yellow. 



— Journ. fiir Prakt. Chemie, vol. Ixv. p. 349. 



