CATALOGUE.—- PyiUMATIC MACHINES. 



S59 



Account of the explosion of Trevithick's 

 steam engine. Repert. ii. III. 394. Ph. M, 

 XVI. 372. 



Saint's patent steam engines. Repert. ii. III. 

 408. 



The flue carried through the boiler. 



On the force of steam engines. Nich. IX. 

 214. 



Perier on the employment of the steam en- 

 gine in coal mines. M. Inst. V. 360. 



Edelcranz's safety valve for emitting steam 

 or admitting air. S. A. XXII. 329. 



Tn the original form of the steam engine, the pressure of 

 steam, and not that of the atmosphere, forced down the pis- 

 ton. Kobison. Enc. Br. 



Mr. Watt finds it most advantageous to work his engine 

 at a high temperature. Robison. Enc. Br. 



The whole force obtained from steam stopped when it 

 has filled one fourth of the cylinder, appears from calcula- 

 tion to be twice as great as when it is continually admitted. 

 Robison. Enc. Br. But perhaps a greater quantity of heat 

 would be required. 



The boiler should contain about ten times as much steam 

 as the cylinder. M.Young. 



An account of Mr, Symington's new Steam Boat. From 

 the Journals of the Royal Institution. I. 195. 



Several attempts have been made to apply the force of 

 steam to the purpose of propelling boats in canals, and 

 there seems to be no reason to think the undertaking by 

 any means liable to insuperable difficulties. Mr. Syming- 

 ton appears already to have had considerable success, and 

 the method that he has employed for making a connexion 

 between the piston and the water wheel is attended with 

 many advantages. 



By placing the cylinder nearly in a horizontal position, 

 he avoids the introduction of a beam, which has always 

 been a troublesome and expensive part of the common 

 steam engines : the piston is supported in its position by 

 friction wheels, and communicates, by means of a joint, 

 with a crank, connected with a wheel, which gives the water 

 wheel, by means of its teeth, a motion somewhat slower 

 than its own ; the water wheel serving also as a fly. The 

 steam engine differs butlittle with respect to the condensation 

 of the steam, from those of Boulton and Watt now in ge- 

 neral use ; there is an apparatus for opening and shiitting 

 the cocks at pleasure, in order to revert the motion of the 

 boat whenevei it may be necessary. The watet wheel is si- 



tuated in a cavity near the stern, and in the middle of the 

 breadth of the boat, so that it becomes necessary to have 

 two rudders, one on each side, connected together by rods, 

 which are moved by a winch near the head of the boat, so 

 that the person who attends the engine may also steer. It 

 has been found most advantageous to have a very small 

 number of float boards in the water wheel. 



Another material part of the invention consists in the 

 arrangement of stampers, at the head of the boat, for the 

 purpose of breaking the ice on canals, an operation which 

 is often attended with great labour and expense. These 

 stampers are raised in succession by means of levers, of 

 which the ends are depressed by the pins of wheels, turned 

 by an axis communicating with the water wheel. 



Mr. Symington calculates, that a boat capable of doing 

 the work of twelve horses may be built for eight or nine 

 hundred pounds. An engine of the kind has been actually 

 constructed at the expense of the proprietors of the Forth 

 and Clyde navigation, and under the patronage tf the go- 

 vernor. Lord Dundas : it was tried in December last, and 

 it drew three vessels, of from flo to 70 tons burden, at the 

 usual rate of two miles and a half an hour. Mr. Syming- 

 ton is at present employed in attempting still further im- 

 provements, and when he has completed his invention, it 

 may, perhaps, ultimately become productive of very exten- 

 sive utility. 



Steam Air Pump. 



Carradori on Berretray's steam air pump. 

 R02. XXXVIII. 150. 



Inflammable Vapours. 



Street's patent inflammable vapour force. 



Repert. I. 154. 

 •fBarber's patent for procuring motion by in- 

 flammable air. Repert. VIII. 371. 

 A stream of ignited air impelling a fly wheel. 



Gunnery. 



Theory of Gunnery, and Operation of Powder. 



See Projectiles. Resistance of Fluids. 

 Hooke's powder proof. Birch. I. S02. Fig. 

 Greaves on the force of guns. Ph. tr. 1685.. 

 XV. lOQO. , . 



