SCIENCE NOTES.

Otago Witness, Issue 3111, 29 October 1913, Page 68

SCIENCE NOTES.

—Clever Life Jacket. — A new jacket, invented by M. Aliain Redou, of Havre, consists of a strong vest equipped with inflatable rubber crowns or tubes, resting on the shoulders and passing under the arms, and covered with material like the vest. A leather belt keeps the vest in place. When required, the tubes are tilled by blowing into them, and in a test the garment was put on and completely inflated in 87 seconds. A sailor with his logs tied and a 221 b weight attached to his feet easily kept above the surface of the water. —Starlight.— Stare shine by their own light—i.e., by the light waves engendered by their terrific heat and propagated through the ether. Planets shine by reflected light —in the case of the planets of the solar system that of the sun. vVhat is known as the secondary light of the moon —the ashy light that is seen over the rest of the lunar globe when the moon is at crescent—is light reflected from the earth, which, of course, gets its own light —i.e.. the light that makes it visible to the other planets—by reflection from the sun. —About Magnets. — The most powerful and permanent magnets are made from steels containing about 6 per cent, of tungsten and 0.5 per cent, of carbon. The magnet bars are to be long and narrow, and after forging at the lowest possible temperature should be heated to 900 deg Centigrade, kept at 750 deg for a time, then cooled off, and for hardening are to be reheated, cooled . gradually to 700 deg, and plunged into brme at 20deg. Maturing is effected by boiling 10 or 1" hours. The bars are magnetised by means of electro-magnets, and when the magnetisation is to remain extremely constant it is induced 5 or 70 per cent, by exposure to demagnetising forces. —Speed of Animals. — No animal is known to have exceeded the speed attained by the horse. Instantaneous photographs of one famous specimen showed the full length of one complete stndy of about 26ft. In the stride of the fastest racers the .hindquarters and limbs are raised considerably higher than the shoulders, and from this relatively great height the legs are brought downward and forward, widely separated from each other to avoid striking the forelegs. The hare has not in reality the speed of the nog. The dog, on the other hand, does not attain the speed of the horse. The giraffe is said to ran at the rate of 15yds per second under the most favourable conditions. The elephant, going at the rate of 2yds a second, carries a weight approximating that carried by six horses. —A Midge that Carries Fever. — Professor Townsend, of Lima, has discovered the transmitter of the “Verruga Peruana” in a midge called “Phlebotomus, a genus of the family of Psychodidse, or owl-midge, of the sub-order of Orthorapha Nemocera. This fly is a sniall, moth-like, hairy midgo, which when flying carries its wings over its head, and at rest folds them over its back in a slanting fashion, like the roof of a house. The veins on the wings are nearly parallel, and the sixth and seventh are indistinct. The “Phlebotomi’ aro scattered throughout the tropicai and sub-tropical belt, and fly sluggishly, but they can run well. According to Grassi, of Dalmatia, and Professor Doerr, they lay their eggs in dark places and in the crevices of walls, and die soon after. The eggs hatch in a week into larvae, which are cylindrical, and live in stagnant water and decaying vegetation, and pass in eight weeks into punre, having two tubular ‘ stigmata, and after two weeks the puparium burets and lets out the nymph, which flies away, the species “Phlebotomus papatacei” is known to lie the carrier of the so-called “seven days'’ fever. This fever is contracted only where this fly exists, and nowhere else. The virus transmitted by fly to patient is filterable, and is closely related to those of “dengue” and “yellow fevers.” —Electrical Exercise for the Fat— The usual remedy for obesity is underfeeding or muscular exercise, and either may have bad effects in the enfeebled condition of many fat persons. French experiments having shown that electric stimulation may give automatic exercise of the muscles 'without fatigue, Dr Nagelschmidt, a Gorman physician, lias had built a spe-cially-designed apparatus for applying such treatment to the obese. As described by Dr A. Gradcmvitz, this apparatus consists of a strong wooden reclining chair, with insulated metal surfaces serving as electrodes, two electrodes for the patient’s back being adjustable bv racks, two being placed on the scat, two for the calves arranged on an adjustable foot-rest, and two others -for abdomen, and two for the thighs or chest on special side-supports. By 10 small commutators a switchboard connects each electrode either to a positive or a negative pole, each electrode having its speciallyregulated resistance. By a special commutator. driven by a little electric motor, the supply current is transformed into an alternating current, and this for muscular stimulation may reach a frequency a-s high as 7000 periods a minute. The electric treatment has the same effect in reducing flesh as ordinary muscular exercise, with no harmful consequences. Besides its use for producing muscular contractions, the intermittent, current is adapted for other purposes, and may be made to give local or even general anaefcheevi. —Trick Ventriloquism.— Invention is by way of displacing the ventriloquist, who nowadays is reallr Ho ventriloquist at all. When ho isn’t irpeaking his own lines he is puffing vigorously at a big black cigar, and how can a man do that and talk for hia dummy, visibly or invisibly, at the same time? The answer is, ho can’t. At a recent enter-

tainment given by the employees of a big electric company ono of the features of the programme, says Life, was a “ventriloquist” act. The performer was assisted in his specialty by a little wooden dummy styled “Know-it-all.” The little fellow not only talked remarkably well, but moved his head and arms and worked his jaws like a regular lightning-rod agent. As an encore, he sang one of Caruso's selections, and the audience was about ready to vote the performer the champion ventriloquist, when, to the amazement of all, the full orchestral accompaniment of song came from the little man. In order to produce these mysterious effects the dummy figure is fitted inside with a loud-speaking telephone receiver, with a horn or large mouthpiece pointing towards the audience. The receiver in turn is connected with a special transmitter, which is handled by an operator in an ante-room some distance away. An ordinary operator’s breast transmitter is also concealed in the body of the dummy. Whatever is said by the man on the stage is transmitted via the dummy to the operator behind the scone, thereby enabling him to hear what the ventriloquist says, and to make the proper reply for the dummy. When speaking into the special transmitter, the operator, by means of a telegrapher’s key which controls an electromagnet, causes the dummy's jaws to move so that the words apparently come from its mouth. With other keys he is enabled to turn its head and to move its arm and foot. The wiring from the megaphone receiver and from the relays which operate the dummy’s jaws, head, arms, and feet is run down the two front logs of the chair on which the figure sits.