SCIENCE AND INVENTIONS.

New Zealand Herald, Volume LI, Issue 15664, 18 July 1914, Page 4 (Supplement)

SCIENCE AND INVENTIONS.

FINDING LONGITUDE.

The novel method of finding longitude lately tried by Professor Lippmann, the French astronomer, is tho comparison of simultaneous photographs of the sky taken at two stations. The zenith being shown by an artificial star, the difference in the places of natural stars very accurately indicate:/ the difference in longitude, and if tho longitude of one place is known that of the other can be fixed with an uncertainty claimed to bo only a few feet— perhaps 10 or 15. WATER-PROOFING FOR RUBBERS. The members of the staff of Mount Rose Observatory, Nevada, have found shellac to be an impervious and pliable waterproofing for rubbers, which otherwise during a day's use on the snow-fields absorb sufficient moisture from tho snow to dampen the feet. An application of J lie shellac at infrequent intervals kept the rubbers in perfect condition. It, was also found that a coating of shellac on the thongs of stiowshoes prevented them from becoming quickly watersoaked on wet snow, and so eliminated much of the sag-, ging and heaviness that form a serious drawback to walking on webbed snowshoes over melting snow. Thongs coated with shellac also dried after becoming wet much more quickly than thongs uncoated. ROAD-MENDING MACHINE. An experimental test has been made in Paris of a portable road-mending machine, consisting of a six horse-power gasoline engine, actuating an air-compressor, tho air being led from a storage tank to a pneumatic rammer and a pneumatic pick, the latter being described as morely a modification of the well-known pneumatic rivetter. The workman holds the tool close to the road and pushes the pick under tho surface, raising it up as he proceeds. It is said that tho work was done at a much faster rate than was possible with the ordinary pick. The pneumatic rammer also gavo good results. One advantage of tho system is that several men can work from tho same compressor plant. The trial seemu to indicate that mechanical road-mending is more effective than the present method.

DUST AND ELECTRICITY. A curious experimental electrical machine described by Mr. W. A. Douglas Rudgc to tbo Cambridgo Philosophical Society depends on dust. When clouds of dust are raised, either by the wind or by artificial mew*, they are always strongly charged with electricity, which is positive or negative, according to the nature of the material; and it is possible to obtain a continuous supply of electricity by using suitable apparatus to drive a dust-laden stream of air through an insulated tube. While the dust is passing, the tube will yield a steady stream of sparks, sometimes moro than' 2in long. The air escaping also carries a charge, which in a room may be retained balf-an-hour or more. The charge is probably duo both to the actual raising of the cloud and to friction of the dust against the tube. Such dust may be used as flour, sulphur, road dust, or fine iron filings.

WAYE-MAKING MACHINE. A machino has been invented which will make, to your liking, any one of a halfdozen or more different kinds of wavesocean waves, long rolling billows, short choppy waves, and, among others, the white-cap variety. It is possible to have a real Milford surf just by switching on an electric motor, which sets four plungers in motion. These plungers work up and down in the water, and the different ways the plungers arc worked make the different kinds of waves. For instance, if long rolling billows are desired, the plungers arc worked in unison. If' a short choppy sea is wanted, the plungers are worked independently of each other; when whitecaps are wanted, two plungers are worked up and two downthis combination causes tho waves to break into white-caps. The different combinations of the plungers result in the different kinds of waves. ARTIFICIAL rEGS. It is not often that an infirmity carries with it the possibilities of making a fortuno, but this is what seems to havo happened to M. Desoutter, the young French aviator, who had his leg amputated as tho result of a flying accident about two years ago. | He has invented an artificial leg, tho improvements in which should ensure great commercial possibilities. In an interview ho described how, after a year's misery and discomfort with the ordinary false leg, he started experimenting on ono which would be lighter than those made by tho usual makers. "Whv," ho said, "you can't walk more than 50yds without; feeling done up. In walking you, of course, swing each leg, and you can't swing an artificial leg weighing anything from 61b to 101b very far." The artificial limb devised by the young Frenchman weighs only 21b, and its chief factor is an alloy of his own discovery, in wL'ch aluminium figures. whether in consideration ; of tho weight of one's natural lee 21b was not too light, M. Desoutter replied tint if it could weigh nothing at all it would be so much the better. "Another thing | you must remember is that artificial limbs have to be supported by straps over the shoulders and round tho waist, and the more the weight the moro you are pulled forward." Unlike those made bv surgical instrument makers, the one-legged aviator's j production is padded from the knee to the ankle, so, as he humorously described it, "if you crack your leg in netting off a 'bus everyone does not look round first of all to wonder, and then to decide that 'the poor fellow's got a wooden leg.'" "TJNTAPPABLE" WIRELESS. Remarkable success in the- recording of printed messages by wireless telegraphy has been achieved with an invention of Captain A. N. Hovland, of the Norwegian Navy. A simple keyboard similar to that of a typewriter is employed for transmission, and the inventor has already typed messages by wireless betweon Berlin and the big station at Nauen. Tho results were at times somewhat uncertain owing to the absence of a sufficiently sensitive relay by which the feeble wireless signals could be rendered powerful enough to operate tho typewriting device. Captain Hovland, however, has now produced an instrument which will respond to signals of the order of strength employed in wireless work. He states his intention of now applying it to the practical working of his typing device. The chief feature of the wireless typewriter is its application to secret code work; as the apparatus now exists, it is possible at a few seconds' notice to employ any one of 720 different "alphabets." The transmitting keyboard is arranged with an additional alphabetchanging device fixed to it. The keyboard appliance can be applied to any wireless station, and may be used alternatively with the ordinary Morso apparatus. The advantage of Captain Hovland's system is that, although any one of the 720 code alphabets may be used, the receiving apparatus in each case, when set in response, registers the code signals as printed letters of the alphabet, and thus while "tapping" would bo rendered quite, impossible, the messages are recorded in a decoded and legible form. Only dots are used in the transmission— short signals—and by their spacing the mechanism of the rcceivin" apparatus is controlled so as to reconstruct the message. Tho new relay depends upon the variations in the electrical resistance of selenium, the illumination of the selenium cell being controlled by tho movements of a very delicate galvanometer of special design.