Science and Invention.

Alexandra Herald and Central Otago Gazette, Issue 445, 27 October 1904, Page 7

Science and Invention.

THE tremendous power of the swordfish has often been evidenced by a ship's side being pierced with the terrible weapon which gives the creature its name. Pour or five inches of solid timber have been thus penetrated, tho sword being broken off and left in the wood. These fish are plentiful off the island of Martha's Vineyard, on the coast of Massachusetts, and its flesh being much valued, it is harpooned in great numbers; and many are the stories told of the narrow escapes encountored by its captors through its pugnacity. One of them deals with ah experience niet with last summer, when a man in a small boat proceeded from a fishing smack lo secure a wounded fish which was motionless and apparently exhausted. But no sooner was the harpoon line moved, than tha fish made a struggle for life, and aftor d:'.ving once, with the,objcct of spearing the boat, and missing his aim, the fish dived a second time, and succeeded in driving his sword completely through the boat from side to side. By constant baling, the boat was kept afloat until assistance arrived, when it was found that the intruder weighed three hundred and thirty-eight pounds.

With the advent of rapid-fire guns for naval use, it became evident that something more than water-tight compartments was required to protect a ship's side against shot-holes ; and the plan generally adopted is that of the copper dam, or double skin, packed with some material which, after passage of a projectile, would expand and seal the wound against intrusion of. water. The material adopted British navy has been'ia mixture, of cork and oakum, and in the ease of H.M.S.'. Inflexible,, the total amount,of packing aggregates in; weight no less than one hundred and forty-three tons. In the United States navy, the same duty has been fulfilled by the use of cellulose, obtained from the husks of coca-nuts. Becently, however, a better material has been found in the pith of corn-stalks, which has been granulated by machinery. In recent trials it waS shown that this material kept the water out afterpassage of a shot most efficiently. Jt'b.e pith is

about, one-sixth the weight, bulk for bulk of the mixture of oakum and cork.

Y-SECTIOfI RAILS. The T-seotion is so universally used for rails that it is a novelty to consider any other form or to think that any other practical shape might have any advantage. However, a German rail section is being introduced in'jthe United States which is of inverted V-shape, the inner and outer lines being parallel, so that the same pair of rolls may be used for rolling rails of different weights. Moreover, the face of the rail is rolled harder than is possible with a T-section. It is claimed that this roll has six times the lateral strength and one-half more vertical strength than the present Tsection rail of equal weight. With this rail no splice-bars or bolts are used at the joints, the connection being made simply by using a short section of the same weight of rail placed underneath and within the V's of the track-rails, so as to bridge the joint. By the use of wood blocks fitted in the V between the rail and the tie, a large elastic bearing is secured, The rail is held to the ties by spikes the same as the T-rail now in use,

A CtfAINLESS, GEAR DRIVEN JfIOTOR BICYCLE. The ' ' has" its engine, which rotates in the same direction as the line of travel, securely bolted in a.vertical position to the frame. Upon an extension of the engine crankshaft is a bevel-wheel, at right angles to which is fitted' a light shaft having at each end bevel wheels in constant mesh with- that on the crankshaft, and a toothed wheel fixed to the hub of the rear road wheel. All these wheels are entirely encased and run in grease. A clutch is fitted on the propeller shaft, operated by tho hand lever in starting, and usually the speed is controlled by the pedal, providing a free engine for traffic, descending hills, etc. The transmission is thus direct to the rear road wheel. Footrests are provided, enhancing the rider's comfort, but ordinary pedals and chain can be had instead. The engine has mechanically operated valvos, which arc placed across the front of the motor, instead of at the side as usual, consequently receiving a full current of air for cooling. The cylinder and head are a single casting. The carburettor is of' the spray type, and the ignition is by means of brush contact with accumulator and trembler coil.

.A NEW ELECTRIC CLOCK. The electric clock invented by Mr George S. Tiffany, of 30, Rose Street, New York city, is simple in construction, the v/orking parts consisting mainly of an electromagnet, a pivoted armature, a pawl mounted on the armature and engaging a single ratchel-wheel, to the arbour of which is attached the minute hand. The ordinary train of wheels is dispensed with. A slowbeat torsional pendulum carrying a contact arm momentarily closes the circuit of the electro-magnet and a battery, at regular intervals determined by' the beat of the pendulum. The armature, moving in response to the influence of the magnet, propels the ratchet-wheel and hands. As the pendulum has no mechanical work to perform in operating the clock, and consequently no frictional loads, it is obvious that perform its functions as a periodic time interval device in a most perfect manner. Varying friction loads, which in the movement of a clock of the ordinary type would seriously affect its operation, are of comparatively small importance in this clock. It is evident, therefore, that a clock upon this principle may be crudely constructed, yet be capable of keeping good time. The action of the clock is very similar to that of a secondary clock controlled by an independent pendulum. A number of these clocks may be operated in synchronism by removing the pendulums from all but one clock, and using this as a master clock with the others connected properly in circuit. The current consumption is very small. One good dry cell will operate the clock' for many months, and when exhausted may be renewed at a nominal expense.