80 Comparison of the Blowpipe of Hare and Brook. 
gases to flow decidedly to the focus, and with such rapidity 
as to keep up a constant supply. “As there is nothing to 
confine the stream of =—- reacting force, crag 
to Pow, it is diminished, Bey coe in a ge- 
and it is very soon reduced to a pressure 
not superior o cheat exerted in Mr. Hare’s. From the small 
capacity of the reservoir, the entire duration of one charge 
of gas is also very short, and it is burnt out in a minute or 
wo. It is true, it is possible i in some measure to compen- 
sate for this defect, b Sie Sale an assistant to inject 
rare while | ame urning, but this, besides the 
onvenie 1 ngs ; woul oes occasion "Scuba 
ones a fore penn ienad to the resistance ‘of tl » walls 
of the re 
servoir, and might therefore “= inet with 
even fatal veloc ney S 
* That thi gras is not aaboteidey. will vt arent from the fol- 
lowing fact. been acenstomed (borrowing the experiment from 
the late Dr. Woodhacee of Philad elphia) to mix fulminating n er ir 
tmuriate (chlorate) of potash by agitating them on an open paper by @ 
feather ; they _ ewes red into the. bowl of epoes mon tob 
hy SORES. ipa pat from a long facia the explo- 
z iolent, —- happened from the fine frag- 
pe hoaiga: ways b 
On one ootine We sabstitated fort eee bowl, a oe tinplate ¢ can- 
Besitinguie er, placing it with the vertex,of course, downwards, in an iron 
