338 NOTICES OF THE MEETINGS [June 10, 
useful purposes which suggest themselves at once, or which may 
hereafter be developed. The principle of the process is to heat 
baryta in close vessels and peroxidize it by the passage of a current 
of air; and afterwards by the application of the same heat, anda 
current of steam (with the same vessels) to evolve the extra portion 
of oxygen, and receive it in fitly adjusted gasometers: then the 
hydrated baryta so produced is dehydrated by a current of air 
passed over it at a somewhat higher temperature, and finally 
oxidized to excess by the continuance of the current and a lower 
temperature : —and thus the process recurs again and again. The 
causes of failure in the progress of the investigation were described 
as detailed by M. Boussingault; the peculiar action of water illus- 
trated ; the reason why a mixture of baryta and lime, rather than 
pure baryta, should be used, was given; and the various other 
points in the Mémoire of M. Boussingault* noticed in turn, That 
philosopher now prepares the oxygen for his laboratory use by the 
baryta process. 
The next subject consisted of the recent researches of MM. Frémy 
and E. Becquerel, on the influence of the electric spark in converting 
pure dry oxygen into ozone. The electric discharge from different 
sources produces this effect, but the high intensity spark of the 
electric machine is that best fitted for the purpose. When the 
spark contains the same electricity, its effect is proportionate to its 
length ; for at two places of discharge in the same circuit, but with 
intervals of 1 and 2, the effect in producing ozone is as | and 2 
also. A spark can act by induction ; for, when it passes on the out- 
side a glass tube containing within dry oxygen, and hermetically 
sealed, the oxygen is partly converted into ozone. Using tubes of 
oxygen, which either stood over a solution of iodide of potassium or, 
being hermetically sealed, contained the metal silver, the oxygen 
converted into ozone was absorbed; and the conversion of the whole 
of a given quantity of oxygen into ozone could be thus established. 
The effect for each spark is but small; 500,000 discharges were re- 
quired to convert the oxygen in a tube about 7 inches long and 0.2 
in diameter into ozone. For the details of this research, see the 
Annales de Chimie, 1852, xxxv. 62. 
Mr. Faraday then referred briefly to the recent views of Schén- 
bein respecting the probable existence of part of the oxygen in oxy- 
compounds in the ozone state. Thus of the peroxide of iron, the 
third oxygen is considered by him as existing in the state of ozone ; 
and of the oxygen in pernitrous acid, half, or the two latter propor- 
tions added when the red gasif formed from oxygen and nitrous gas, 
are supposed to be in the same state. Hence the peculiar chemical 
action of these bodies ; which seems not to be accounted for by the 
* Annales de Chimie, 1852, xxxv. p. 1. 
