Pumps. Acid. - Although this device, in slightly different forms, has been in use for some time, yet the convenience of the modification shown in Fig. 269 may render it worthy of description. ABC are 3 glass tubes passing through the rubber stopper D, A and B ending just below the stopper, and C reaching to the bottom of the bottle. To B is attached a double-valve rubber bulb. A is so bent that while the bulb is clasped in the hand, the thumb can easily be held over the open end of A at H. Acid can then be forced out through C, and the flow may be checked instantly by removing the thumb from H. The left hand is thus left free to hold under C the vessel into which the acid is to flow. A glazed earthenware dish is placed upon the table under C to catch the drippings-Far the use of large classes of beginners in general chemistry this apparatus is well adapted, since accidents resulting from careless handling are rendered almost impossible, and both acid and time are economised. The same device may be used for carboys, the tube C being extended upward, so that an acid bottle may stand on the box beneath it, and H being kept closed by a piece of rubber tubing and a pinch cock. (L. M. Dennis in Amer. Chetn. Jour.)

Doulton and Co., of Lambeth, hare for some yeara past devoted special attention to the subject of stoneware pumps for acids, and have spared no effort 10 produce a thoroughly efficient and reliable apparatus. The original design has been greatly modified, and the present pattern shown in Fig. 270 embodies all the improvements suggested by many years' practical experience. Each pump, before being supplied, is put into actual work with a 30-ft. head of water and tested as to efficiency, and so to ensure satisfactory working. They are strongly constructed of acid-proof stoneware, plunger and valves also being of this material. The valves and sentthe valve-box covers, and the lift of the talvea is adjustable. In case of injury to any portion of the pump, it can be replaced at a small coat. The pumps are made in sizes to lift 240- 2000 gal. per boor. They appear to be

Water

The article will treat of the combined application of two natural forces to the elevation of waler. These forces are: first, the heat of the atmosphere; and second, the comparatively low temperature of the water to be raised. Fig. 271 shows the general arrangement of an apparatus worked on this principle. This apparatus has been built at Auteuil, where it operates very well, although the French climate is not favourable to the operation of such a F is a smalt building covered by a roof E, which is exposed to the south, and this roof is formed of 10 metallic plates, which are numbered 1, 2, 3, i, 5, 6, 7, 8, 9,10. Each of these plates consists of 2 sheets of iron riveted together on all their edges, and separated slightly by filling pieces. Each plate thus constitutes a water-tight receptacle, in which a volatile liquid can be held. Various liquids can be used, but preference is given to a solution of ammonia. Under the influence of atmospheric heat, the solution emits vapour, and these vapours or gases escape through tubes, one of which is provided for each plate, and are conducted to the receptacle N. Any liquid which may have been carried along by the gas is taken back to the plates by a tube.

By another tube the gas escapes from the vessel N. This gas has a pressure of 1, 2, or 3 atmospheres, according to the work which is to be done. It is conducted through a tube to a hollow sphere, which is placed in the well or tank from which the water is to be elevated. This sphere contains a rubber diaphragm, which can attach itself to either half of the sphere.

Acid pump.

Acid pump.

Stoneware told pump.

Stoneware told pump.

Water 500168

Let us suppose, for instance, that the sphere is full of water; the rubber diaphragm, consequently, will rest against the upper half or hemisphere. If, now, the pressure of the ammonia gas is brought to bear on the diaphragm, it will be forced to rest on the lower nemisphere; but in order to do this, the diaphragm must eject the water which fills the sphere. This causes the formation of a jet of water, as shown above the tank R near the letter G. But the gas must be driven from the sphere after it has been emptied of water, so that the operation may be renewed. This is accomplished in the following manner: In the centre of the diaphragm a float is inserted, which carries a rod by which a slide is actuated. One of the apertures in this slide coincides with the gas inlet, and the other with the outlet. When the diaphragm rests on the upper hemisphere the inlet is opened, and the water escapes; when it moves toward the lower hemisphere the inlet is closed, the outlet is opened, the sphere is filled with water again, and so on.

This would complete the operation if the ammonia gas did not cost anything; but as it is expensive, it must be used over and over indefinitely. Here we arc aided by the low temperature of the water, which is made to pass through a serpentine pipe contained in a watertight vessel containing part of the ammonia solution used. The solution is cooled by the water in the pipe, and is ready to absorb ammonia. Then, as soon as the outlet is opened, the ammonia gas conducted into it is absorbed, the pressure which was exerted in the sphere is removed, and water can again enter the sphere. A final precaution is taken, which is to attach a little pump to the float, by means of which the ammonia solution can be pumped back into the roof E.

The apparatus at Auteuil raises over 300 gal. of water per hour. In warm countries, the same apparatus would raise 792 gal. a distance of 65 ft. The calculation of the results to be obtained by this apparatus is based on the following considerations:

A sheet of metal 1 yd. square absorbs 11 calories for a difference of 1° C. Each plate which has a surface of 4 sq. yd. absorbs 44 calories per hour. If there is a difference of 6 °, 264 calories will be taken from the atmosphere every hour; and by combining this quantity of heat with the cooling action of the water, it is easy, by the difference of tension produced, to obtain an inexpensive force for raising water.

This apparatus differs from the numerous devices by which attempts have been made to utilise solar heat by means of the Archimedean mirror, by which only secondary heat is obtained. It is not necessary totoncentrate the heat by metallic or other mirrors; the atmospheric heat is the basis of the operation, and all roofs exposed to the sun can be used for this purpose. In this manner a valuable motive power can be obtained in warm countries without loss of room. Generating plates, such as described, can be applied to any roof, and if we consider, that with only 10 such plates 792 gal. can be raised 65 ft. per hour, we can easily understand that a great elevating power can be obtained by increasing the number of plates. (La Nature.)