Mr. Leeson on a Self-acting Blowpipe. 237 
another sort haying a browner colour, which is much less yielding 
in its substance, and cannot be extended to the same thinness as 
the former. 
I have found both sorts to answer my purpose, but the above 
observations may be useful in determining the quantity of air which 
may be condensed into the bottles with safety. 
To apply these bottles when filled with condensed air, nothing 
more is necessary than to remove the syringe, and in its place to- 
screw on a jet of such bore as may be required. On opening the 
cock the air will be expelled by the elasticity of the India Rubber, 
and its own condensation, in a strong and uniform stream, which 
in bottles of the size I have mentioned will continue from twenty= 
five minutes to an hour, according to the size of the jet. 
When once prepared the bottles may be constantly expanded to 
the same dimensions without any danger of bursting. When the 
air is exhausted, the bottles will be found somewhat enlarged in 
_ dimensions, but may again be contracted by holding them before a 
- fire, or a few minutes’ immersion in boiling water. This, however, 
is unnecessary, since no subsequent inflation will be found to in- 
crease the size of the bottle any further, and I have used the same 
repeatedly without any apparent diminution of its elastic powers. 
The principal advantages of this blowpipe are its great portability, 
and length and steadiness of action, (in which I consider it much 
superior to the hydraulic blowpipe,) together with the perfect liberty 
at which, when properly mounted, it leaves the operator’s hands. 
This blowpipe is applicable to any of the gases, and may, I cons 
ceive, be applied with advantage to contain the explosive mixture of 
oxygen and hydrogen, as no inconvenience can possibly accrue 
from its bursting, beyond the loss of the bottle. 
This blowpipe may be supplied with air or gas during an ex- 
periment, by having a separate communication for the syringe into 
the piece of tube before mentioned, and this will enable the ope- 
rator to continue his experiments for any period of time. 
Blowpipes on this construction may be procured, very neatly and 
conveniently mounted, at Mr. Newman’s, No. 8, Lisle-Street, 
. Leicester-Square. 
Vo. XVII. Ss 
