112 Sullivan on the Revolving Engine. 
but its great utility will be found in facilitating water car- 
riage on those rivers, which are at times shallow, and those 
which are rendered more extensively navigable by canals 
around their falls. 
I am, very respectfully, yours, &c. 
J. L. SULLIVAN. 
Boston, October, 1819. 
P.S. Inthe Hartford Boat, we used the Tar or Gas 
fire with good effect : but I am not able to state yet, precise- 
ly the proportion of saving. The men about the engine 
however, thought it equal to as much again wood as they 
used. 
When I have made some decisive trials I shall communi- 
cate the result. 
Riemark. We understand that Mr. Sullivan and Mr. Mo- 
rey have in the investigation of the economy of the liquid 
fuel of steam engines, (or tar and steam fire,) made some 
discoveries and improvements which bid fair to be very use- 
ful and economical. ‘They are in practice ina steam en- 
gine which carries the recently invented self directing lathe, . 
which makes ships’-blocks, lasts and other irregularly form- 
ed articles. 
Haplangtien of the plates referred to in the preceding communi- 
cation. 
Index to the annexed plate of the Revolving Steam Engine. 
aaa Boilers, 
bb Cylinders, 
ec Counterpoise, (not absolutely necessary as the Seas 
counterpoise each other. ) 
dd _ Frames holding the cylinders, &c. 
ee Axes on which the frames rotate, 
*f Fixed cranks or centers, 
gg ‘The pitman or bar, 
hh Cross pieces, 
it The Piston rods, 
xk The Ribs which preserve the parallel movement of the 
rods, 
il The rotary valves, 
mim The fixed counterpart to the rotary valve, 
