382 Steam Engine. 
engine to the whole process of weaving. His improve^ 
ments consist in 
5thiy. A new and ingenious method of giving the ne- 
cessary perpendicular motion to the piston-rod. 
In condensing the steam, by expanding it in a very thin 
surface between hollow metal balls cooled withinside the 
inner one, and withoutside the outer one by cold water ; 
so that a great surface of steam is exposed to the action 
of cold, as a great surface of wick in Argand'^s lamp is 
exposed to an inside and outside current of air. 
He attempted to save much trouble usually necessary 
in packing the piston, by fitting accurately a metal piston 
to the cylinder, by means of springs that keep the piston 
in close contact with the inner side of the working cylin- 
der. 
As he pumps i-ip all the steam thus condensed, into the 
boiler— and as this steam is condensed without intermix- 
ing with the cold water used for condensation, his princi- 
ple admits of the use of ardent spirits^ if this liquid should 
at any time ot for any reason be preferred. 
I do not know whether Mr. Cartwrights engines are 
much in use^ An account and drawing of it, I have al- 
ready given ; another engraving of it may be found in 
1 Tilloch’s Philos* Mag. 1* 
Gthly* Mr. Hornbbwets improvements do not seem 
to consist in the adoption of any new principle, for rea- 
sons stated by Professor Robison^ in the article steam en- 
gine in the Edinburgh Encyclopasdia^ p, 771, (which 
with the supplement ought to be perused) but in the 
methods used to make his collars air tight-^ — in the struc- 
ture of his condensing vessel, and in the framing of his 
beams. A plate of Hornblowets engine is given by 
Professor Robison in that article^ and by Dr. Gregory in 
the second volume of his Mechanics* 
7thlyi Mr* improvenients consist 
