124 ANNUAL OF SCIENTIFIC DISCOVERY. 



rollers from the pulp engine, or else through fine hair sieves, in the same 

 manner that paper is made. The sheets of tobacco thus made from pulp are 

 formed into cigars and cheroots. 



COMPOSITION FOB RENDERING FABRICS WATERPROOF. 



Payen, the eminent French chemist, has prepared the following composi- 

 tion to be used in rendering clothing for the French army waterproof: 

 Dissolve two pounds and a half of alum in four gallons of water ; dissolve also, 

 in a separate vessel, the same weight of acetate of lead in the same quantity 

 of water. When both are thoroughly dissolved, mix the solutions together, 

 and when the sulphate of lead resulting from this mixture has been precipi- 

 tated to the bottom of the vessel in the form of a powder, pour off the solution, 

 and plunge into it the tissue to be rendered waterproof. Wash and rub it 

 well during a few minutes, and hang it in the air to dry. 



VENTILATION OF MINES. 



The London Mining Journal describes a new method devised for ventilating 

 mines. It consists of a reservoir, or hydro-pneumatic box, placed on one side the 

 adit level, supplied with water from a cistern on the surface. A metallic tube 

 descends from the cistern to the vessel in the adit, and the supply is regulated by 

 a self-noting valve. At the top of the metallic tube is a glass case, nicely regu- 

 lated by a slide, which being suspended at a certain point admits no more water 

 than is necessary. To draw in the largest possible quantity of air, a vortex is 

 formed, and a continuous stream of air and water, varying in proportion accord- 

 ing to the distance between the reservoir and the hydro-pneumatic box, is con- 

 veyed from the former into the latter. Here the water and the air are sepa- 

 rated, the former escaping at the self-acting valve, and the latter being forced 

 through a main tube, which branches off to any part of the mine. 



CHIMNEY REGISTER AND WEATHERCOCK. 



Mr. J. A. Royce, Lee, Mass., has made an improvement in the above by 

 which to avoid a greater consumption of fuel during windy weather than there 

 is in fair weather. On the top of the chimney is placed a device similar to an 

 ordinary slatted hot air register. This register has a vane and rudder, and is 

 turned to the proper position by the action of the wind against the rudder, 

 and its slats, after it is thus moved, are closed more or less by the action of 

 the wind against a sail, which is on a mast projecting up from the slats. 

 When the wind blows hard, the slats are operated so as to almost entirely 

 close up the flue of the chimney and thus diminish the draught, and when it 

 is calm they open the flue and thus increase the draught. 



IMPROVED LITHOGRAPHIC PRINTING PRESSES. 

 In order to give a uniform and forcible impression to all parts of the stone 

 in lithographing, with the expenditure of but a very small amount of power, 

 a press with the following improved arrangement has been devised : A wood 

 or metallic air-tight chamber or tub, containing water or other fluid, with its 

 bottom or one side composed of india rubber, or some other waterproof, elastic 



