138 Progress in Science. (January, 
Fig. 9, No. 2. The neutral oxychloride has avery great general absorption, and 
shows some bands, but is almost devoid of fluorescence. The uranic oxyfluoride 
gives a spectrum generally resembling the acetate, normal sulphate, &c., and 
shown in Fig. 11, No. 2. The absorption-spectrum is likewise well marked, 
and is shown in Fig. 12, No. 2. When dissolved in water and acidulated 
with hydrofluoric acid, it yields the absorption-spe@rum No. 3 of Fig. 12. 
Of the double oxyfluorides the potassium salt is the most brilliant, and is 
represented in Fig. 11, No. 1, its absorption-spectrum being shown in Fig. 12, 
Fic. 14. 
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No. x. Of the fluorides examined none show any fluorescence, but their 
absorption-spectra are well worthy of notice. That of the uranous salt is 
shown in Fig. 13, No. 2, and that of the potassio salt in Fig. 13, No. r. Uranic 
formiate gives no fluorescence, and shows an absorption-spectrum with faint 
bands. The uranic nitrate fluoresces brilliantly, yielding what may be called 
the normal uranic spectrum. It shows an absorption-spetrum of well- 
marked, regular bands. All the oxalates yield absorption-spectra, which are 
very well marked, and seem identical, carrying out the idea above suggested 
Fic. 15. 
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as to the breaking up of double salts when dissolved. The phosphates, like the 
arseniates, show a remarkable fixity of spectrum, but the absorption-spectra 
present a variety of forms. The absorption-bands of the neutral and acid 
sulphates are shown in Fig. 14, Nos. 1 and 2, and in 3 we find the bands of 
any other uranic sulphate as yet examined. It would seem with the sul- 
phates as with the acetates that all are reduced to the same condition when 
in solution. Fig. 15 shows the absorption-spectra of the following double 
sulphates :—(1) ammonio-uranic sulphate; (2) ammonio-diuranic sulphate ; 
(3) magnesio-uranic sulphate; (4) rubidio-uranic sulphate; (5) sodio-uranic 
sulphate; (6) thallio-uranic sulphate. For a detailed description of the 
characteristics of the various spectra here mentioned the reader is referred to 
