class="ctr">THE CHINESE PUMP.

We speak here of a glass tube, because with this the phenomenon may be observed. Any tube, of course, would produce the same results.

The manufacture of the apparatus is very simple. The tube is closed above or below, according to the system one desires to adopt, by means of a perforated cork. The valve is made of a piece of kid skin, which is fixed by means of a bent pin and a brass wire (Fig. 2). It is necessary to wet the skin in order that it may work properly and form a hermetic valve. The arrangement of the lower valve necessitates the use of a tube of considerable diameter (Fig. 1). We would advise the adoption of the arrangement shown in Fig. 2. Under such circumstances a tube half an inch in diameter and about 3 feet in length will answer very well.

It is better yet to simply use one's forefinger. The tube is taken in the right hand, as shown in Fig. 3, and the forefinger placed over the aperture. The finger should be wetted in order to perfect its adherence, and should not be pressed too hard against the mouth of the tube. It is only necessary to plunge the apparatus a few inches into the liquid and work it rapidly up and down, when the water will rise therein at every motion and spurt out of the top.

This is an easy way of constructing the Chinese Pump, which is found described in treatises upon hydraulics. Such a pump could not, of course, be economically used in practice on account of the friction of the column of water against a wide surface in the interior of the tube. It is necessary to consider the pistonless pump for what it is worth—an interesting experimental apparatus that any one can make for himself.—La Nature.

THE WATER CLOCK.

To the Editor of the Scientific American:

Referring to the clepsydra, or water clock, described and illustrated in the SCIENTIFIC AMERICAN SUPPLEMENT of December 20, 1884, it strikes me that the ingenious principle embodied in that interesting device could be put into a shape more modern and practical, doing away with some of its defects and insuring a greater degree of accuracy.

Fig 1.

I would propose the construction given in the subjoined sketch, viz.: The drum, A (Figs. 1 and 3), is mounted in a yoke suspended in such a manner as to bring no unnecessary, but still sufficient, pressure on the friction roller, B, to cause it to revolve the friction cone, C (both cone and roller being of wood and, say, well rubbed with resin so as to increase adhesion).

Fig 2.

The friction roller should be movable (on a screw thread), but so arranged that it can be fixed at any point, say by a lock nut, screw, clamp, or other simple means. It will be evident that, by shifting the roller, a greater or less speed of the cone can be effected, and as to the end of the cone's axis an index hand sweeping an ordinary clock face is attached, the speed of this index hand can be regulated to a nicety, in proportion to that of the drum. Of course, before fixing the size and proportion of the disk and cone, the number of revolutions of the drum in a given time must be ascertained by experiment. For instance, the drum being found to make 15 revolutions in 12 hours, the proportions would be:

Or, the drum making 2½ revolutions in 3 hours, equal to 9 revolutions in 12 hours:

Any slight inaccuracy can be compensated by the cone and disk device.

The drum, or cylinder, is caused to gradually revolve by a weight attached to an endless cord passing once around the drum. The latter might be varnished to prevent slipping. The weight should be provided with an automatic wedge, allowing it to be slipped along the cord in an upward direction, but preventing its descent. The weight is represented partly in section in the engraving. This weight should not be quite sufficient to revolve the drum, it being counterbalanced by the liquid raised in the chambers of the drum. The liquid, however, following its tendency to seek the lowest level, gradually runs back through the small hole, D, in the partitions, but is continually raised again, with the chamber it has just entered, by the weight slightly turning the cylinder as it (the weight) gradually gains advantage over the as gradually diminishing weight of each chamber raised.

As to the drum, the same might be constructed as follows, viz.: First solder the partitions into the cylinder, making them slanting or having the direction of chords of a circle (see Fig. 2). The end disks should be dish shaped, as shown. Place them on a level surface, apply heat, and melt some mastic or good sealing wax in the same. Then adjust the cylinder part, with its partitions, allowing it to sink into the slight depth of molten matter. In this way, or perhaps by employing a solution of rubber instead of the sealing wax, the chambers will be well isolated and not liable to leak. The water is then introduced through the center openings of the disks before hermetically sealing the drum to its axis.

Fig. 3.

The revolving parts of the clock being nicely balanced, a pretty accurate timepiece, I should think, would be the result. It is needless to mention that the "winding" is effected by slipping the weight to its highest point.

Of course I am far from considering the above an "instrument of precision," but would rather look upon it in the light of a contrivance, interesting, perhaps, especially to amateur mechanics, as not presenting any particular difficulties of construction.

ED. C. MAGNUS.

Crefeld, January 5, 1885.

NEW TORPEDO.

We illustrate a new form of self-propelling and steering torpedo, designed and patented by Mr. Richard Paulson, of Boon Hills, Langwith, Notts. That torpedoes will play an important part in the next naval war is evident from the fact that great activity is being displayed by the various governments of the world in the construction of this weapon. Our own Government also has latterly paid great attention to this subject.

The methods hitherto proposed for propelling torpedoes have been by means of carbonic acid or other compressed gas carried by the torpedoes, and by means of electricity conveyed by a conductor leading from a controlling station to electrical apparatus carried by the torpedo. The first method has, to a considerable extent, failed on account of the inefficient way in which the compressed gas was employed to propel the torpedo. The second is open to the objection that by means of telephones placed in the water or by other signaling apparatus the torpedo can be heard approaching while yet at a considerable distance, and that a quick speeded dredger, kept ready for the purpose when any attack is expected, can be run between the torpedo and the controlling station and the conductor cut and the torpedo captured. The arrangements for steering by means of an electrical conductor from a controlling station are also open to the latter objection. The torpedo we now illustrate, in elevation in Fig. 1, and in plan in Fig. 2, is designed to obviate these objections, and possesses