Miscellaneous Intelligence. 285 
inder, is two feet or so thick, the interior being filled with clay and 
charcoal to prevent the conduction of heat through from below. 
On one side of either large cylinder near the bottom, there is an open- 
ing for the entrance of the air for raising the piston and for its passage 
out as the piston descends; and close by this opening, just outside, 
isa mesh-work of wire, called the regenerator, through which 
the air passes, both on entering and going out. This regenerator is 26 
inches high and wide, and is filled with 200 disks of wire-net, having 
10 meshes to the inch, making 67,600 meshes in each disk, and 
000 in the whole regenerator, forming thus an apparatus for cool- 
ing the air that leaves the engine, and at the same time for warming 
the air that enters. There are 414 miles of wire in each regenerator, 
and the amount of surface it presents is 2014 square feet, equal to the 
entire surface of 4 steam boilers, 40 feet long, and 4 feet in diameter. 
The air going out loses about 480° F. of its temperature, and the same 
amount is the next mom municated to the air passin in. 
The supply-cylinder, (upon each working cylinder,) is simply a pump 
for pumping in air. As its piston descends (simultaneously with the 
working piston), a valve at top opens from external pressure, and air 
sin from without. On rising, the pressure closes this valve, and 
opens another ; and through the latter the air passes into a flue, opening 
into the air-receiver—a large rectangular box placed vertically, meas- 
Piston, ‘Thus there is a free communication for the air from the upper 
cylinder (the supply-cylinder) through the air-receiver alongside into 
‘rough the air-recciver and regenerator to the lower cylinder below 
the piston ; and So it goes on as just described. 
. We have thus given the particulars respecting one of the great cyl- 
inders, and its subsidiary supply-cylinder. The other of the pair is 
Secoxp Semis, Vol. XV, No. 44—March, 1853. 37 
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