1816.] Description of a new Blow-Pipe. 367° 
to leave the bird they live upon, and even remain after the bird is 
dead. How far does the complete perfection displayed even in the 
simplest and meanest parts of creation bafle our comprehension, 
both with respect to their mechanism and utility, and evidence the 
hand that formed them ! 
M. W. Carocan. 
Sa eS 
ArticLe VII, 
Description of anew Blow-Pipe. By H. 1. Brooke, Esq. 
(To Dr. Thomson.) 
DEAR SIR, 
I seND you enclosed a drawing of a blow-pipe which I have lately 
had made upon a principle I believe entirely new in its application 
to this instrument, and which I have 
reason to believe, from the power 
which it possesses, and the facility 
with which it may be used, is an 
improvement upon any that has 
fasirace it. The occasion of my 
aving it made was to relieve the 
great inconvenience I felt in using 
the common blow-pipe with the mouth, The first idea that sug- 
gested itself to me was to produce the jet of air from a sort of arti- 
ficial mouth, or moveable receiver, of rather large dimensions, the 
capacity of which should be capable of gradual reduction by means 
of a spring ; but it immediately occurred to me that the elasticity 
of the air itself, if forced into a fixed receiver, would be more 
uniform in its action than any spring, and might be regulated so as 
to produce a continued and more uniform jet. I accordingly applied 
to Mr. Newman, in Lisle-street, to make one upon this principle, 
to consist of a copper or iron vessel, into which the air 4s forced by 
a small condensing syringe, and from which it is suffered to escape 
through a tube of very small aperture, regulated by a stop-cock ; 
and I have found it capable of affording a very intense and regular 
degree of heat. The form given in the drawing has been adopted 
by Mr. Newman for the convenience of packing into a small case ; 
and he has also added to the syringe a screw, by means of which 
the receiver may be filled with oxygen or any other gas, which 
renders it more extensive in its application to chemical purposes, 
and probably so as to supersede the use of the common gazometer. 
Jam, dear Sir, your obedient servant, 
_ Keppel-street, April 8, 1816. H. I, Brooke, 
