SCIENTIFIC.

Press, Volume LII, Issue 9124, 7 June 1895, Page 2

SCIENTIFIC.

A recent despatch from Quebec to a New York paper says that the successful tempering of aluminum, so as to give it the consistency of iron, is the latest triumph of F. AUard, the Levis blicksmi.b, whose rediscovery of the lost Egyptian art of hardening copper startled the mechanical world some three or four years ago, and only failed to make the fortune of its owner because of the expensiveness of the process. A recent trial of Allard's tempered aluminum has proved the success of his new method, and the practical purposes to which it can be applied. He has made and hardened a cannon, which has just been tested in the presence of Colonel Sp-nca, the American Consul at Qaebec, with the greatest success. This cannon is 2G inches long and 5 inches in diameter, the metal of the gun outside the bore being only a quarter of an inch thick. A charge, co.isisting of a pound of powder, has been successfully fired out of this little piece of ordnance without having any appreciable effect upon it. A new and more scientific trial of the cannon has been ordered by the Canadian military authorities to be held at the Quebec Citadel by the artillery ex. perts there, and the United States Consul, in view of this move, is understood to have encouraged Mr AUard to manufacture, as speedy as possible, a cannon twelve feet in length for shipment to Washington. The great advantage of cannons made of aluminum, everything else being equal, lies of course in the ligbtuessof the metal. The cannon just tested at Quebec weighs 141b. If it were of iron and tbe same dimensions it would weigh 1801b. Allard's friends and military enthusiasts assert that if tbe tempered aluminum supersedes iron for the making of big guns, field artillerymen, instead of being dependent upon horses and gun carriages for dragging their weapons over rough country, will ba able to shoulder them like muskets. In appearance the finished specimen looks as though ie was made of burnished silver.

The recent electrical discoveries of Mr Nikola Tesia have challenged Edison in the estimation of scientists, and may even presently do so in that of commercial men. The Century Illustrated gives a description of the latest form of his " oscillator," the new motor which combines in one mechani_m both dynamo and steam engine, and produces a new kind of current, capable of delivery over very slender wires ab extraordinary pressure, and at great distances :—" The crude idea of obtaining currents by means of a coil or a magnetic core attached to the piaton of a reciprocating steam engine is not in it.elf an entire novelty. It may also be noted that steam turbines of extremely high rotative velocity are sometimes used instead of slow moving engines to drive dynamos. But in the first class of long abandoned experiments no practical re>ult of any kind was ever reached before by any sort of device; and in the second class there is the objection that the turbine is driven by means of isolated shocks that cannot he overcome by any design of the blades, and which frustrate any attempts to perform work of the kind now under survey. What we are dealing with here is a dual, interacting machine, half mechanical, half electrical, of smallest balk, extremely simple, utilising steam under conditions unquestionably of the highast efficiency, its vibrations independent- of load and pressure, delivering currents of the greatest regularity ever known for practical work or research. That such a combination should produce electricity for half the consumption of steam previously necessary with familiar apparatus in equivalent results need no. surprise us; yet think how much a saving of that kind would mean in well nigh every industry consuming power 1" By tho alternating

current, used as the sun uses the 6th_t light is produced without heat in certaii gases; that is to say, these are made ti vibra'e with the rapidity of liaht waves and that when simply approached wlthU a few inches of the terminal of a coil. More than this, Mr Tesla has found how to draw off elec! riclty from the earth in its normal state. Of transmission without) wires, the dream of all who are new engaged in electrical ret-e-rch, Mr Tenia ia sanguine. It is to be achieved, he think*, by the method of attuning two electrical systems, so that, like tuning forks, one may set the other vibrating. "My conviction has grown so strong that I no longer look upon this plau of energy or intelligence transmission as a mar. theoretical possibility, but as a serious problem iv electrical engineering which must be carried out some day. The ideaol transmitting intelligence without wire is the natural outcome of the mo9t recent results of electrical investigations. Some enthusiasts have expressed their belief that telephony to any distance by indue tion through tbe air is possible. I cannot stretch my imagination so far; but I do firmly believe that it is practicable to dU. turb by means of powerful machines the electrostatic condition of the earth, an_ thus transmit intelligible signals and perhaps power. In fact, what ia there agairub the carrying out of auch a scheme? We now know that electric vibration may be transmitted through a single conductor, Why, then, not try to avail ourselves of earth for this purpose? We need not.. frightened by the idea of distance. To the weary wanderer counting the mile posts the earth may appear very large -, but to that happiest of all men, the astronomer! who gaze, at the heaven 9, and by their

{standard judges the magnitude of out globe, it appears very small. And ao I think it must seem to the electrician ; for when he considers the speed Avith which an electric disturbance is propagated through the earth all his ideas of distance must completely vanish."