1924,.] 
[ 165 ] 
NEW PATENTS AND MECHANICAL INVENTIONS. 
== 
To Mr. Samurt Brown, of Printing- 
house Square, Blackfriars, London, for 
~ a Pneumatic or Gas-Vacuum Engine. 
With an Engraving. 
NEVERAL attempts have been made 
KD by ditterent gentlemen, to render the 
yower obtained by the expansion of explo- 
sive mixtures available for the purpose of 
propelling machinery : but all attempts 
of the kind have been rendered abortive 
by the extreme rapidity and uncontroul- 
able violence of the expansive force. 
The application of chemical and mecha- . 
nical agency combined, of which Mr. 
Brown’s new engine is the result, is so 
far from any thing like accidental dis- 
covery, that it should be considered, 
according to our view, as a most de- 
cided triumph of the power of inven- 
tion, in reducing the hitherto most re- 
fractory chemical agency to the domi- 
nion and controul of man. 
' We do not wish, to indulge in any 
speculations as to the ultimate advan- 
tages that may accrue from the applica- 
tion of this invention (not only in Great 
Britain, but also in the Continental 
States and America, to which it seems 
the patent right is extended). We can 
no more imagine what will’be the ex- 
tent of its application than it could 
haye been imagined by a Warr or an 
Arkwricnt, that their respective inven- 
tions were destined within the period of 
half a century to quadruple, or we might 
almost say to centuple, the internal 
rich and resources of their native 
ie ah whilst it disseminates her pro- 
ductions. of art and industry through 
every region, from “ Indus to the pole.” 
_ We should now wish to proceed im- 
mediately with a description of the new 
vacuum engine, by referring the reader 
to the accompanying plate. But we feel 
it somewhat incumbent on us to say a 
few words as to the chemical principles 
on which its action depends, in order to 
render our description more intelligible ; 
and also for the purpose of doing justice 
to the scientific acumen, as well as the 
mechanical ingenuity of the inventor. 
We could rather wish the task to have 
devolved on the patentee himself as the 
most proper person to have described 
his own views. But as the specification 
only refers to the principle of effecting 
a vacuum by the combustion of inflam- 
mable gas, sufficient to render the me- 
chanical adaptation for producing it 
intelligible to ordinary readers, we will 
endeavour te illustrate that principle by 
a few remarks, before describing the 
apparatus by which it is effected. 
From the earliest discoveries con- 
nected with gaseous bodies, it was as- 
certained that all the inflammable gases 
consume more or less oxygen during 
their combustion ; which oxygen is sup- 
plied by the atmospheric air in every 
case where inflammable substances, either 
solid, liquid, or gaseous, are employed 
for yielding artificial light—The two 
former classes being in all cases reduced 
into gaseous matter by the heat of a 
flame, previous to their giving out light 
and heat for the purposes of domestic 
and civil economy. 
Direct experiments have shewn us the 
precise quantity of oxygen consumed 
by different kinds of inflammable gas. 
Thus pure hydrogen, ‘at a red _ heat, 
unites with, or condenses, half its own 
volumes of oxygen-gas, producing a vio- 
lent detonation; and at the same instant 
forming a particle of water about the 
two thousandth part of the bulk of the 
original gases. Sub-carbureted hydro- 
gen, or coal-gas, requires, however, for 
its most perfect combustion, nearly dou- 
ble its own bulk of oxygen, or about 
the proportion of 5:9 of the latter. 
The result of which combustion is, a 
volume of carbonic acid gas, the bulk of 
the inflammable gas; with a particle of 
water (or aqueous vapour condensed) as 
before. Carburetted hydrogen. or oil- 
gas consumes upwards of three times its 
bulk of oxygen during its combustion, 
leaving more than two volumes of car- 
bonic acid, and a particle of water or 
aqueous vapour, according to the tem- 
perature of the vessel. : 
The mixture of all these gases with 
their respective proportions of oxygen 
before-mentioned, produces a most vio- 
lent detonation, accompanied by great 
expansion. The inflammability of hy- 
drogen gas is such, that. when mixed 
with oxygen in almost any proportion, 
the union is so instantaneous on apply- 
ing a lighted taper, that great expan- 
sion, followed by the collapse of the 
ambient air, always ensues. Pure hy- 
drogen is, therefore, a very dangerous 
agent to employ for any inflammable 
process, from the uncontroulable vio- 
lence of its attraction for oxygen. 
But during the consumption of a jet 
of oil-gas or coal-gas for giving artificial 
light, the supply of oxygen from the 
atmosphere air is so gradual, that we 
obtain a combustion without explosion. 
Now 
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