~~ 
= 412, _ Hare's sulfite, gc. 
thus the receiver, and the exterior bell glass. The interior 
bell and tube might then be fastened together, by grinding or 
luting. As yet I have only used lutings of waxed cloth, or 
cork. It may be proper to point out, that 3 or more concen- 
tric bell glasses, and 4 or more jars, might be used. The 
union of the bell, receiver, and tube once effected, it is hardly 
more troublesome to use 3 than 2. When the fluid in the 
central jar is saturated, this may be emptied and replenished 
from the middle jar, the latter from the external one. ‘Then 
supplying the external jar anew, the process may be continued. 
The other figures are to explain an apparatus on the same 
principle, constructed of hollow, oblong paralellopipeds, dif- 
fering in length more than in breadth; so as_ to allow a ser- 
pentine tube to wind into the interior, and deliver gas under 
a vessel shaped like a T. * 
Fig. 2. represents a vertical section of the whole as when 
situated for use.* 
"Fig. 3. a vertical section of the lower vessels only. 
Fig. 4. a vertical section of the covers alone. 
Fig. 5. a horizontal section, or ground plan of the lower 
vessels. The upper vessels are so proportioned as to divide 
the distance between the lower ones equally. 
It may be well to mention, that this apparatus, from the fa- 
cility with which it may be cleaned and inspected internally, 
admits of being made of porcelain or stone ware.t I have had 
a cylindrical one constructed of the latter material, in which 
the covers are in one piece, with a tube in the centre for in- 
troducing gas. The apparatus may be made more efficacious} 
by drilling a series of small holes round the brims of the bell 
glasses or covers, so as to cause the gas, instead of passing 
round the brims.in large bubbles, to divide itself into very 
small ones. By this means it will be more thoroughly inter- 
mingled with fluid. 
* Excepting, that the covers ought to be so depressed, that their brims 
may be lower than the bottoms of the interior vessels over which they are pla- 
ced respectively. This is necessary to prevent the gas from escaping, ere it 
have access to the surface of the fluid beneath those bottoms. 
+ The apparatus may also be made of glass bottles, duly proportioned, and 
cut (truncated) alternately near the shoulder and near the bottom. : 
