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WAT?’S LABOURS IN THE STEAM-ENGINE. 389 
men’s engines of known dimensions ; the quantity of 
cold water that must be injected into the cylinder to 
give a certain force to the piston’s descending oscillation ; 
and finally the elasticity of steam at various tempera- 
tures. 
Here was enough to occupy the life of a laborious 
physicist, yet Watt found means to conduct all these 
numerous and difficult researches to a good termination, 
without the work of the shop suffering thereby. Dr. 
Cleland wished, not long since, to take me to the house, 
near the port of Glasgow, whithef our associate retired 
on quitting his tools, to become an experimenter. It was 
razed to the ground! Our anger was keen but of short 
duration. Within the area, still visible of the founda- 
tions, ten or twelve vigorous workmen appeared to be 
occupied in sanctifying the cradle of modern steam- 
engines ; they were hammering with redoubled blows 
various portions of boilers, the united dimensions of 
which certainly equalled those of the humble dwelling 
that had disappeared there. On such a spot, and under 
such circumstances, the most elegant mansion, the most 
sumptuous monument, the finest statue, would have 
awakened less reflection than those colossal boilers. 
If the properties of steam are still present to your 
mind, you will perceive at a glance, that the economic 
working of Newcomen’s engine seems to require two 
irreconcilable conditions. When the piston descends, 
the cylinder is required to be cold, otherwise it meets 
some steam there, still. very elastic, which retards the 
operation very much, and diminishes the effect of the 
external atmosphere. Then, when steam at the temper- 
ature of 100° flows into that same cylinder and finds it 
cold, the steam restores its heat by becoming partially 
