60 ANNUAL OF SCIENTIFIC DISCOVERY. 



water, confined in a copper tube, was invariably frozen before that in 

 the lead. The expansion (about, one ninth) consequent on its crystal- 

 lization, is applied, by a simple mechanical arrangement, to elevate a 

 piston and shut a cock, while the water in the lead pipes is still fluid. 



COUPLING FOR PIPES AND HOSE. 



MR. A. H. BROWN, of Allany, has invented a new coupling for 

 hose and pipes, by means of which a connection between two pipes or 

 pieces of hose is effected by a single motion of the hands. The coup- 

 ling consists of a hollow metal ferrule, attached to the hose in the usual 

 manner. This ferrule is enlarged at its other end, so as to form a cy- 

 lindrical-shaped cup or hollow box, the edge of which is sufficiently 

 thick to form a firm bearing against the flat, corresponding edge of 

 the other coupling. This latter is a hollow metal ferrule, of equal 

 bore to the first one, and its extremity is enlarged so as to form a 

 flange, equal in diameter to the first, coupling. The edge of this 

 flange is turned at right angles to its axis, so as to bear truly against 

 the edge of the other coupling when the two are united. Albany 

 Cultivator, Sept. 



REGISTER HYGROMETER. 



AT one of Lord Rosse's scientific soirees, Mr. Appold exhibited his 

 register hydrometer. This instrument, with a variation of one degree 

 in the moisture, opens a valve capable of supplying ten quarts of water 

 per hour, delivering it to pipes covered with blotting-paper heated by 

 a gas-stove, by which the \vater is evaporated until the atmosphere is 

 sufficiently saturated and the valve thereby closed. A pencil registers 

 the distance the hygrometer travels. 



HYDROSTATIC LOG. 



AT the meeting of the Royal Society, on Feb. 7, Sir Francis Beau- 

 fort, on the part of the Lords Commissioners of the Admiralty, com- 

 municated a description of a hydrostatic log, the invention of Rev. E. 

 L. Berlhon. Its object is to obtain a register of the speed of ships, 

 by a column of mercury, in such a manner that the height of the 

 column shall depend upon the velocity alone, and not be affected by any 

 disturbing causes. The principle embraces that of Pitot's tube, inas- 

 much as the force of the resistance due to the velocity is communi- 

 cated through a small pipe, projecting into the water below the bottom 

 of the ship ; this force, acting upwards, compresses a portion of in- 

 closed air in a small cylinder, which air, communicating by means of 

 a little pipe with the bulb of a glass tube, bent like a common barom- 

 eter, raises the mercury in the tube by depressing it in the bulb. 

 The action of this single column of water and air upon the surface of 

 the mercury in the bulb alone must depend, not only upon the resist- 

 ance due to the velocity, but also upon the distance of the cylinder 

 from thf water-line, which varies with every sea, and it is therefore 



