Description o/'Mr Perkins’s New Steam-Engine. 177 
greater than 6 feet by 8, yet Mr Perkins considers that the appa- 
ratus (with the exception of the working cylinder PP, and pis- 
ton PQ), is perfectly sufficient for a 30-horse engine. When 
the engine performs full work, it consumes only two bushels of 
coal in the day. 
On the application of Mr Perkins's principle to Steam-En- 
gines of the old Construction. 
Great as the invention is which we have now described, yet 
we are disposed to think that the application of the principle 
to old steam-engines is not less important*. When we con- 
sider the enormous capital which is at present embodied in 
Great Britain in the substantial form of steam-engines, and 
the admirable elegance and skill with which these noble machines 
impel and regulate the vast population of wheels and pinions 
over which they reign, we feel as if some vast innovation were 
proposed upon our established usages, by the introduction of 
Mr Perkins’s engine. The very idea that these potentates of 
the mechanical world should be displaced from their thrones ; 
that their strongholds should be dismantled ; their palaces de- 
molished, and their whole affairs placed under a more economi- 
cal management, is somewhat startling to those who dread change, 
and admire institutions that both work and wear well. Mr Per- 
kins, however, has saved them from such a degradation. He 
has allowed them to retain all their honours and privileges, and 
proposes only to invigorate them with fresh influence and power. 
In this new system, the old engines , with their boilers , are re- 
tained unaltered. The furnaces alone are removed. Mr Per- 
kins constructs a generator consisting of three horizontal tubes 
of gun-metal, connected together, filled with water, and sup- 
plied with water from a forcing-pump, as in his own engine. 
This generator is exposed to heat in an analogous manner, so 
that, by means of a loaded valve, which opens and shuts, the 
red hot fluid may be constrained till forced out of the generator 
into the water in the boilers of Bolton and Watt. By this 
means, as much low pressure steam of four pounds on the square 
* This invention appears to have been fully established by direct experiment, 
whereas the new engine , with all its great promise, is still only undergoing trial, 
yoL. IX. NO. 17. 1823. 
M 
