64 ANNUAL OF SCIENTIFIC DISCOVERY. 



On the disk being set in motion, an immediate vacuum is formed at 

 the induction-post, to which the windbore, or suction-pipe, is securely 

 fixed ; the water now rushes up, and fills the space between the cylin- 

 der and disk, which continues until the disk is opposite the delivery 

 point, when the contents of the cylinder are forced out up the column, 

 at the same instant the vacuum is forming on the opposite side, and a 

 fresh supply is following that which is being delivered. The column 

 used was a two-inch pipe, about forty feet high, and the water was 

 ejected in a solid, continuous stream, with the greatest ease, at a ve- 

 locity of two and a half feet per second. A large pump on this sys- 

 tem is in daily use in Yorkshire, draining a marsh, throwing a con- 

 tinuous stream of ten tons of water per minute. London Mining 

 Journal, June 22. 



DIVING APPARATUS. 



THE Farmer and Mechanic for June 20 describes a new diving ap- 

 paratus, the invention of Mr. Kennish. It is constructed of sheet- 

 iron about one fourth of an inch thick. It is about seventeen feet 

 high, twelve feet long, and ten feet wide, and has in the centre of the 

 top an aperture or man-hole, on each side of which are three valves, 

 with leathern hose-pipes for admitting pure air and carrying off that 

 which has become foul. It contains internally two main divisions, 

 which do not communicate, the inner one being devoted to the opera- 

 tions of the divers, and the outer to the purpose of lowering or raising 

 the vessel in the water by means of air. These divisions are both 

 open at the bottom. In working, the air is injected into the inner 

 division by means of an air-pumping machine, and thus the water is 

 prevented from rising in it. The air in the outer division is allowed 

 to escape till the water rises in it to a certain point, thus destroying 

 the buoyancy that would otherwise exist, so that the buoyancy of the 

 inner division is counteracted by the weight of the materials and bal- 

 last. A rope serves to alter the distance between the bed of the river 

 and the bottom of the vessel. To raise the vessel, air is injected into 

 the outer division and the buoyancy thus increased. When the ves- 

 sel reaches the surface the divers escape through the man-hole, and 

 the vessel remains in the water ready to be towed to any other spot. 



NEW AIR-SPRING FOR DOORS OR GATES. 



MR. GEORGE BEATTIE has described to the Royal Scottish Society 

 of Arts a new air-spring for shutting doors and gates, opening one or 

 both ways. This is not a spring, properly so called, but simply a 

 counterbalance, by means of the pressure of the atmosphere made to 

 act towards a vacuum, the resistance being uniform throughout the 

 travel of the door. The air-spring consists of an iron box and cover 

 let into the floor, \vhich contains a vertical axle supported at the bot- 

 tom in a hollow cup, and furnished at the upper end, which projects 

 above the floor, with a shoulder and lever-hinge for carrying the door 

 on this shaft, and within the box is fastened a horizontal wheel, which 



