Science and Invention.

Alexandra Herald and Central Otago Gazette, Issue 440, 22 September 1904, Page 7

Science and Invention.

NEW TURBINE FOR MARINE PURPOSES. PROFESSOR HELE-SHAW claims to have constructed a turbine for marine purposes which can be reversed even if going at 600 revolutions per minute. The reversing power is seven-eighths of the goahead. It is, he contends, contrary to all engineering principles to stop a mass of 3noving machinery • and then use another ongine of small power for reversing purposes, as is. done in turbine vessels now running. • ■■■; SUPERSEDING PNEUMATIC TYRES. Daniel F. Minehan, jun., OFango, N.J., who is coimected with the Edison Works, in Orange, has just got a devioe patented designed to supersode'the pneumatic tire. The wheel, instead of carrying a pneumatic, tube around the tire, carries it in a steel frame around the axle of the carriage. All the jar of the vehicle is therefore taken care of in the pneumatic tube in the axle, and there is no danger of puncture. A STEAM ENGINE WITXOUT FIRE. In Germany, a tireless locomotive is working by steam. It has just been completed at the Hohenzollem works at Dusseldorf, and is one of a type designed for shunting in explosive factories. Instead of carrying fire in its own boiler it is filled with steam from stationary boilers, and when so charged is capable of several hours' work. The first warming up occupies half an hour, and subsequent re-charging can be done in a quarter of an hour. The absence of a fire in a place where dynamite or gunpowder is being handled is the reason for the type of engine which, by the way, is very much the same in principle as the fireless locomotive tried on the Metropolitan railway some thirty years ago, LIGHT. When we speak of an instantaneous exposure, wo think we have given something very short. And it is very difficult to realise that our conception of time, according to human standards, may be very far away from what actually takes place, Now, light is estimated in round figures to travel at 190,000 miles per second, and if we estimate the length of the beam that Is admitted, by our shutter when making a snapshot,, wo shall get some idea of the enormous possibilities of energy oxpended in producing the image. - For' instance, we set our shutter for the l-20th of a second; that moans that a stream of light 9,500 miles long has entered our lens . and impinged on the plate, and even for one thousandth of a second exposure means a stream of 190 miles long to work with ; or, again, if wo have occasion to give five minutes exposure, the light that enters the camera last had not left the sun's surface when wo began the exposure.

AERIAL NAVIGATION,' At the Academy of Sciencos, M. Maurice Levy read a paper on aerial navigation by Colonel Eenard, the Director of the Military balooning establishment at Meudon. Colonel Renard demonstrates the possibility of constructing with the petroleum motors now existing, a flying maching capable of supporting itself in the air. With motors weighing ten kilogrammes per horse-power such a thing -was impossible; but with a petroleum motor such as those constructed, weighing no more than five kilogrammes per horse power, it begins to be feasible. It will become very easy with motors of half that weight per horse-power,and Colonel Renard believes reduction in the weight can be effected without changing the principle of the present petroleum motors. The flying machine would, of course, have to be provided with vory light screw propellers of as perfect shape as possible. Numerous experiments have been made at Meudon with the object of ascertaining the best kind of propeller. A type has been selected and has been named the 'Optima screw,' with which Colonel Renard is certain a flying machine could be made to carry up a motor of 5 H.E., with eight or ten kilogrammes of weight t© spare. For a flying machine provided with a motor to be able to rise into the air, the impetus given by the screw must, of course, be greater than the weight of the motor and the propeller. Colonel Renard calls the difference 'useful weight,' which the apparatus could support in the air. Colonel Renard is convinced that the weight' of the present motors can be greatly diminished. He shows that, with a motor weighing one kilogramme per horse-power, extremely heavy weights could be carried into the air. If the weight of the motor wore only reduced to three kilogramme per horse-power, a flying machine capable of carrying two men could be constructed with his propeller. Colonel Renard expresses the opinion that it would be the aeroplane which will be the flying-machine of the future. M., Maurice Levy is of the same opinion, and points out that a machine constructed as an aeroplane to receive a forward impetus, like a bird on the wing, would require a smaller horsepower than Colonel .Renard calculates for a machine oapable'of-'supporting itself and rising in the ai»jv ' ■