488 



Dr. W, Huggins on the Spectra 



[May 25, 



That these paraffins have really the constitution which I have ascribed 

 to them follows partly from their mode of formation ; thus dipropyl was 

 obtained from the normal propyl iodide, and dibutyl from normal butyl 

 iodide. The constitution of the others was determined by converting them 

 into alcohols and studying the oxidation products of the latter; thus the 

 hexyl hydride from petroleum, as well as that obtained from mannite, was 

 transformed into secondary hexyl alcohol, which on oxidation yielded acetic 

 acid and normal butyric acid. 



In the communication above referred to, I placed the hydrocarbon 

 C 8 H 18 from methyl-hexyl carbinol amongst another group ; but I have 

 found now that this body is identical with dibutyl and also with the hydro- 

 carbon which Zinke obtained from primary octyl alcohol. This chemist 

 prepared also dioctyl, C 1G H 34 , which consequently is a normal paraffin ; 

 and it appears probable that dihexyl, which Brazier and Gossleth obtained 

 by the electrolysis of cenanthylic acid, belongs to this group too. 



We are now acquainted with the following normal paraffins : — ■ 

 Boiling-points. 



Found (mean). Calculated. Difference. 



c h, — — 

 ii ■ — ■ — 



c, II, ■ • 



c .i Hio 



1° 



1° 





C, H, 



38° 



38° 



37° 



C„ H„ 



70° 



71° 



33° 





99° 



100° 



29° 



G, K 



124° 



125° 



25° 





202° 



201° 



4x 19° 



C 16 H 31 



,278° 



278° 



4x19° 



From this it appears that the boiling-point is not raised 31° for each 

 addition of CH 2 , as I formerly assumed, but that, as the calculated numbers 

 show, the difference between the boiling-points of the lower members de- 

 creases regularly by 4° until it becomes the well-known difference of 19°. 



IV. " Note on the Spectrum of Uranus and the Spectrum of Comet 

 I., 1871." By William Huggins, LL.D., D.C.L., V.P.R.S. 

 Received May 10, 1871. 



In the paper "On the Spectra of some of the Fixed Stars"*, presented 

 conjointly by Dr. Miller and myself to the Royal Society in 1864, we gave 

 the results of our observations of the spectra of the planets Venus, Mars, 

 Jupiter, and Saturn ; but we found the light from Uranus and Neptune too 

 faint to be satisfactorily examined with the spectroscope. 



* Phil. Trans. 1864, p. 413 ; and for Mars, Monthly Notices R, Astr. Soc. toI .xrrii. 

 p. 178. 



