To denote the height of water in the boiler there 
is a Standard and Wheel (f) which is connected with 
a Stone Float and Balance Weight, and moves an 
Index, pointing out the level of the water; also for 
the same purpose, two Guage Cocks (gg) and Pipes, 
one on each side of the fire door: these communicate 
at different levels with the inside of the boiler. From 
that on the right hand steam should issue, if opened; 
and from that on the left, water. 
A Mercurial Guage (i) shews the pressure of the 
steam at all times. 
The Furnace (a4) is regulated with the greatest 
precision by a door to the ash pit, and a damper in 
the chimney; the latter is balanced by a weight (5 b) 
descending by a chain over two pullies near the fire 
door, and can be opened or shut in a moment. 
By a brass cock at the lowest part of the boiler, the 
water can be let out, for the purpose of cleaning it, 
which should be done every two or three months. 
We proceed now to describe the arrangement of 
the pipes. The number of these is of course propor- 
tioned to the degree of heat required and the space it 
has to fill. In the Large Stove (No1, Plate 2) which 
is 200 feet long, and contains above 30,000 cubic 
feet, four tiers are laid the whole length in the front; 
with these the heat is quickly raised to 80° or 90°. 
estward the warm greenhouses, No. 2 and 3, have 
each two tiers, and beyond those the small stove, No. 
4, has five. Eastward No 5, 6, and 8, have one, but 
No 7, being so much wider and higher, has three. 
The whole are divided into two separate mains, 
which for the sake of distinction, we may call the 
Eastern and the Western. as its separate 
Cock (11, mm, Plate 1) on the boiler, and these cor- 
PLACES 
