Revolving Steam Engine. 351 
three or four inches above the platform. The sheet iron is con- 
tinued up the outsides of the outer boiler, so as to enclose 
them; and at one end, between the boilers, there are small 
grates for coal or other fuel. 
The tar vessel or vessels are lodged in the space between and 
upon the boilers, and a small fire may be made under them if 
necessary. A pipe leads steam in at one end, two pipes at the 
other; one near the bottom, one near the top, lead out the 
tar and steam. These pipes unite below ; the steam and tar 
thus mingled, in suitable proportions, flow to the plain fire or 
the flues of the boilers, as well as to the coal fire below, where 
the gas and tar are ignited. The fireman judges of the propor- 
tion of each by the effect ; the object being to produce a nearly 
white ffame, without appearance of tar. Thus flame is applied 
to the greatest possible surface, and the apparatus adds very 
little to the cost of the engine.” 
Mr Morey has also made other two improvements upon the 
boiler. The first of these consists in lining or covering the flue 
within with sheet iron or copper, perforated with small holes^ 
reaching down its sides nearly to the bottom. By this contri- 
vance, the water is made to circulate rapidly between the flue 
and the lining up to the top of the flue, and thus protects it 
from being run dry or heated red hot when the water gets by 
accident too low. In consequence of this circulation, the lining 
causes the steam to form much faster. The other improve- 
ment consists in an interior boiler or vessel occupying the back 
part of the flue, and communicating downwards with the water 
and upwards. 
Two engines of Mr Morey’s construction have already been 
erected ; one of them at a glass manufactory in the neighbour- 
hood of New York, and the other for a steam-boat intended 
principally for towing vessels up the river to Hartford. The 
first of these engines has a cylinder only nine inches in diameter., 
and the piston a stroke of only one foot ; and, with steam at 
50 lb. in the square inch, its power will be equal to that of ten 
horses. The Hartford steam-boat is 77 feet long, 21 feet 
wide, and measures 136 tons. The engine with its boiler oc- 
cupies a space of 16 feet by 12, or one-eighth part only of the 
boat ; the cylinders being hung on the timbers of the deck over 
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