280 Scientific Intelligence. 
of the method, especially when iron is present. In this case, the precipita- 
ted phosphate of bismuth always contains iron, unless this metal is presen 
in the form of protoxyd. The process to be pursued in general is as follows : 
1. Treat the weighed substance with an excess of concentrated nitric acid 
by the aid of heat, so as to transform, if necessary, metaphosphoric or vy 
oe 
o 
5 
S 
Ss 
o 
m 
i 
af 
Qu 
oO 
wm 
be] 
e 
§ 
5 
~ 
Oo 
| gl 
o. 
Sa 
at 
g 
= 
> 
b> J 
2 
oO 
Qu 
td 
g, 
iS 
fas) 
=P) 
a 
fee] 
= 
Ss 
GR 
ee 
a 
- 
carbonic acid through the liquid, till the gas no longer darkens paper 
soaked in acetate of lead. 4, An excess of acid nitrate of bismuth is then 
to be added to the filtered liquid, the precipitate allowed to settle, collected 
on a filter, washed with boiling water, dried, ignited and weighed. 5. The 
bismuth may then be removed from the filtrate by means of sulphuret- 
ted hydrogen, and the bases present determined in the ordinary manner. 
—Comptes Rendus, li, 882. W, ©. 
[See on p. 281 an interesting note on this subject by Mr. McCurdy.] 
6. On the preparation of Oxygen.—H. Sr. Cuatr Devitt and Depry, 
in studying the economical production of oxygen upon the large scale, 
a retort of about five litres capacity, filled with thin platinum foil and 
heated to redness. The acid is completely decomposed into oxygen, watet 
and sulphurous acid, which last is absorbed by an appropriate washing 
diethylenic, triethylenic and tetrethylenic alcohols of Wurtz are among. 
at of the reaction and may be separated by a fractional dnt 
‘ zc : es al! 
CH, 
CL, 0 g==C 29H 29 12- 
C,H . 
_is a viscid liquid like glycerine, soluble in water, aleohol and ether, and t 
at about 281° under a pressure of 0-025™™, that is to say almost in vac" 
