It often happens in towns and where manufactories are crowded together, that the supply of water for condensing purposes is very small, and consequently that it attains an inconveniently high temperature under unfavorable conditions of weather, resulting in the deterioration of the vacuum and a consequent increase in the consumption of fuel. To remedy or to diminish this difficulty, Messrs. Boase and Miller, of London, have brought out the water cooler illustrated above. This consists, says _Engineering_, of a revolving basket of wire gauze surrounding an inner stationary vessel pierced with numerous small holes, through which the heated water discharged by the air pump finds its way into the basket, to be thrown out in the form of fine spray to a distance of 20 ft. at each side. The drops are received in the tank or pond, and in their rapid passage through the air are sufficiently cooled to be again injected into the condenser. The illustration shows a cooler having a basket three feet in diameter, revolving at 300 revolutions per minute, and discharging into a tank 40 ft. square. It requires 3 to 4 indicated horse-power to drive it, and will cool 300 gallons per minute. The following decrease of temperature has been observed in actual practice: Water entering at 95 deg. fell 20 deg. in temperature; water entering at 100 deg. to 110 deg. fell 25 deg.; and water entering at 110 deg. to 120 deg. fell 30 deg. The machine with which these trials were made was so placed that the top of the basket was four ft. from the surface of the water in the pond. With a greater elevation, as shown in the engraving, better results can be obtained. [Illustration: IMPROVED WATER COOLING APPARATUS.] The advantages claimed for the cooler are that by its means the temperature of the injection water can be reduced, the cost and size of cooling ponds can be diminished, and condensing engines can be employed where hitherto they have not been possible. The apparatus has been for two years in operation at several large factories, and there is every reason to believe that its use will extend, as it supplies a real want in a very simple and ingenious manner. Messrs. Duncan Brothers, of Dundee and 32 Queen Victoria Street, E.C., are the manufacturers. * * * * * CORRUGATED DISK PULLEYS.