44 ANNUAL OF SCIENTIFIC DISCOVERY. 



and allows any rain or other water which may accumulate in the boat 

 while in suspension to drain out through the upper perforations. Pro- 

 vision is also made for the retention of water in boats when in the 

 davits, as often such is rendered necessary, by the addition of a 

 " turn-table" at the top, which, being turned round, closes the upper 

 perforations, and retains the water in the boat. The object of this 

 simple but important invention is to guard against the frequent casual- 

 ties which occur Avhen, in cases of shipwreck, or vessels striking on 

 rocks, the ships' boats are suddenly lowered into the water to afford 

 means of escape to the passengers and crew ; but in too many instan- 

 ces the boats become immediately filled, and swamp, owing to the 

 neglect or forgetfulness of stopping the plug-holes which all boats have 

 in their bottoms for their drainage, while suspended along the ship's 

 side. The patent accomplishes this important result with unerring 

 certainty, and by its self-acting principle requires no attention ; and, 

 while it answers the object of drainage of the old method of plug- 

 holes while in suspension, the act of immersion instantaneously closes 

 the orifice by the pressure of the external water against the ball. 



ERICSSON'S CALORIC ENGINE. 



WE copy the following popular description of this much talked-of 

 engine, from Hunt's Merchants' Magazine. 



This invention, by Capt. John Ericsson, Avas first brought before 

 the public in 1833, at London, where he made an engine of five 

 horse power, and exhibited it in operation to several scientific gentle- 

 men. It was timidly, but generally, approved, by intelligent men ; 

 but Brunei (the engineer of the Thames tunnel) and Prof. Faraday, 

 decided against the feasibility of the machine, and by means of the 

 powerful indirect influence of that decision, the English Government 

 which had at first seemed inclined to give the matter their atten- 

 tion let it drop, and it was soon forgotten by the public. Latterly 

 Mr. E. has revived the Caloric Engine in this country, and built two 

 or three, which have been in successful operation. 



It is stated in the journal above referred to, that his Caloric 

 Engines are at work in the foundry of Messrs Hogg and Delamater, 

 in New York ; the one of five, and the other of sixty horse power. 

 The latter has four cylinders. Two, of seventy-two inches in diame- 

 ter, stand side by side. Over each of these is placed one much 

 smaller. Within these, are pistons, exactly fitting their respective 

 cylinders, and so connected that those within the lower and upper 

 cylinders move together. Under the bottom of each of the lowev 

 cylinders a fire is applied. No other furnaces are employed, 

 Neither boilers nor water are used. The lower is called the working 

 cylinder ; the upper, the supply cylinder. As the piston in the sup-, 

 ply cylinder moves down, valves placed in its top open, and it 

 becomes filled with cold air. As the piston rises within it, these 

 valves close, and the air within, unable to escape as it came, passes 

 through another set of valves, into a receiver, from whence it has to 



