Chemistry and Physics. 61 
to this mixture, bubbles of spontaneously inflammable silicide of 
hydrogen were evolved and ignited. Pure and dry silicon added 
to argentic fluoride at a temperature of low redness evolved much 
heat with violent action, and set free metallic silver. The fluoride 
when fused is rapidly decomposed by sulphur with evolution of 
sulphur i i ing formed. 
as a very powerful dusty odor. Sulphur rapidly decomposed an 
4Agh+CS,—2Age,5+ €F,. 
The tetra-fluoride is Sains “acid I ies ag E. Phil. Mag., 
May, 1872. Tage 
5. On a method of fiaing the Constitution of Acids and Alco- 
hols by the oxidation of their Ketones.—In his researches upon 
the oxidation of ketones, Poporr observed a uniformity of results 
Which led him to suggest this oxidation as a means of determin 
ing the rational constitution of acids and alcohols. Taking the 
~ Varieties of ketone expressed by the following general form- 
(1) CH, Sat (CHy)n — CO — R 
(2) == CH — (CH,), —CO—R 
(3) CH 
sot —CO—R 
sae —CO—R 
ho 
by the acid 
eve: this method may be used to determine the constitution of the 
the noe tadical which is contained in any acid. 
alec) > acids may be obtained by oxidizing the corresponding 
Sohols, the constitution of these latter may also be determi 
y this method. : * 
a re ‘est the method, amyl aleohol—of boiling point 130° to 1915 ; 
nN whose power of rotation in a tube 25 cm. long was —2'4°,— 
