286 Liare’s Blowpipe. 
seale without danger. 3d. The power of varying the rela- 
tive proportions of the gases so as to oxydate, or deoxydate, 
as may be desirable. "This power is given by the common 
blowpipe, though in a different way, and is well known to 
be very useful. 
To me it is ludicrous that the author should suppose ae 
ceneey: - exist between the phenomena of the gas 
pipe, and those of volcanoes. 
In ates to put the gas blowpipe into operation, it is im- 
dispensable nes there should be hydrogen and oxygen gases 
confined u moderate and equable compression, so as to 
flow out Geiguhey from a common aperture, at which they 
may be ignited. How are these requisites to be obtained 
in nature? Whence the pure hydrogen or oxygen? Has 
Dr. Clark, or any other person, known them to be extri- 
cated in purity? I[s not the former always carburetted or 
pee and the latter never purer than in the atmos- 
When obtained by art, fire is requisite to liberate 
aaa but in nature the fumes of the fire would con- 
hydrogen. eoahs supposing the gaseous materials gene- 
rated, where is the presiding demon with the genius to de- 
pone eas and skill to regulate that due admixture of them which 
ts i g discovered to be necessary, an 
ined ng that there could be in nature any competent substi- 
tute for ;human agency in a process so intricate, by what 
means, in operations so rude and extensive, is that retro- 
cession of the flame to be prevented, to obviate which, in 
operating with his minute apparatus, a caviltacy tube has 
found indispensable. In subterranean caverns, the 
gaseous elements of water might create explosions, but 
could hever support the pee heat requisite to fuse ab 
ifice be made smaller, and the gases mix ata greater distance from the 
place of effiux, valves should be interposed in the ines, or the should 
be kept under eguable e pressure, as itis possible that if — to unequal 
pressure, the gas whieh i is more pressed, may pass from one re rvoir to the 
y- This, ho bs acl is an over’ 
ae not ak to a place, : as itis so evidently accompanied by a waste 
— persis ——- ardly be so-careless as not to close the 
Closing the fact the usua! 
aaeotion Dinesuhine the fame ssn nS in : 
