SCIENCE NOTES.

Otago Witness, Issue 2167, 5 September 1895, Page 48

SCIENCE NOTES.

• . • Professor Bell believes that telephoning by means of a beam of light will yet be commercially practicable. This belief has grown out of a long coarse of experiments with selenium, which is marvellously sensitive to the influence of light, when exposed to which it gives vibrations that can be electrically transmitted. Professor Bell's story of the way in which he became convinced of the possibility of telephoning without wires is interesting. Some years ago be bad fixed a thin, highly-polished reflector in such a position that it directed the light from a distant scboolhouse roof through the window of bia laboratory-in Washington, and a friend who was aseis' ing him stood on the scboolhouie roof. A-> Professor Bell described it : " A bit of selenium was placed in a teßt tube and all was in readiness. All of a sudden, as I was listening, out of a sunbeam came these words, •Mr Bell, Mr Bell 1 If you hear what I say come to the window and wave your annß."' Professor Bell considers the success of these experiments as even more wonderful and of greater significance than was the discovery of the telephone, whioh has become such A marvellous factor, an

essential element, in medern business ard development.

• . • Katbbun'a watar motor ia a wheel which ra»y be run wLea either partially cr entirely submerged, ia deftigncd to be very efficient in proportion to the speed of the current, and has a very simple and easily actuated mechanism for throwing it into and out of gear. It has been patented by Mr Beuiarnin F. Rithbun, No. 99 VVinslow avenue, Buffalo, New York, and its inventor reports having made some highly satisfactory tests of its efficiency. On a common shaft is a series of wheels, as many as desired, according to the width of the stream, there being on the sides of the wheels outwardly swinging gates adapted to close into recesses in the sides of the wheels when the motor is not in gear. The end wh«e!s have gates on their inner bides onty. The gates on one tide of a whsel are connected together by chains, so that when one gate swings out to the current it pulls the next one open. OppoMte the gates are holes preventing excessive suction and permitting the current to enter and assist in turning the wheel, but the holes on the end wheels have their outer sides partially covered by deflectors. When the gates open, their inner edges strike against the teeth of ratchet wheels on the shaft, these teeth serving as abutments. Parallel with the shaft are rods on which are 1 arms adapted to turn opposite the gates to hold them closed, but which may also be turned back of the gate hinges to permit the gates to swing outward. The rods parallel with the shaft have end crank arms projecting through slots of two concentric wheels, the outer one of which has teeth to engage a pinion, and these wheels being movable in relation to each other. The gatea are held normally locked by the parallel rods, but by pushing the pinion into engagement with the outer wheel the gates are permitted to swing into the current. The machine is thrown out of gaar by a pawl or arm engaging the crank arms on the parallel rods. The motor is well adapted to be placed in a stream, to be run by the force of the current. — Scientific American. • , • While most things nowadays are machine-made, the familiar cigar has hitherto resisted all mechanioal attempts to fashion it, and has continued to be literally " manufactured "—that is, made with the hand. But at last a contrivance has bsen introduced by the Honduras Government BankiDg and Trading Company which is said to conquer all difficulties, and to turn out machine-made cigars of far more perfect shape and finish than those due to the most nimble fiDgers. The foundation ox insido of the cigar is placed in a mould, and four curod iawfl prtsf It Jntoshaoa. The

outside wrapper of tobacco is then fed into the rm chine by an attendant, is rolled round the monlded part automatically, and ifl finally sealed at the pointed end by a drop of gum, which presents itself at the right time and place. The cigars so made are uniform in length and shape, and the leaf in the interior i« so evenly, distributed that the " draw " is far better than in many bandmade cigars. The contrivance is known as the " Jean Reuse Cigar-making Machine."

• . • Everyone who has read Poe'a " Stories of Mjrstery " will remember his vivid description of a descent into the Maelstrom, and will learn wilh interest that M. Latruffe, a well known French aeronaut, has arranged to mako an ascent in a special balloon now being made for him and to anchor bis b<«)l)on immediately over the great whirlpool, thence to obtain a number of photographs, which.it is hoped, will assist towards the clearer understanding of various matters in connection with the Maelstrom, about which, hithorto, scientists have remained in considerable doubt.

••• Dr Hoebar has been making j»om« interesting experiments to ascertain whether the presence, of water weeds affcets the vitality of anthrax germs in water. For this purpose he constructed small freshwater aquaria, each of which contained about eight litres of ordinary river Main water, some river sand, and a supply of water weedp, and in addition about 200,000 anthrax microbes. These aquaria were only submitted to diffused light, and were kept at lOdeg and 19deg C. respectively. Dr Hoeber presumably worked with anthrax bacilli only, but special precautions were not taken to ensure the absence of spores ; no anthrax germs, however, could be found after three days at the lower and four days at the higher temperature respectively. In his second reporb to the Royal Society, Fro* fessor Percy Frankland states that sporiferous anthrax retained their vitality in ordinary river Thames water for upwards of seven months without losing their virulence ; but when exposed to sunshine they were destroyed after 84 hours. On the other hand, when using anthrax bacilli free from spores, as derived from the dead body of an animal, the same authority states that in sterilised river Thames and loch water they were destroyed in about five days at sdeg 0., and in 14 days at 13deg C; but that at lOdeg O. they multiplied enormously, and were present in large numbers on the fortysecond day. This different behaviour wag found to be due to the bacilli having formed spores in the water at the higher temperature. The danger of anthrax germs gaining access to water depends, therefore, upon tho temperafcuro of th* water and the presence

oi absence of spores in the morbific material. Judging by Dr Hoeber's experiments, it jTOUId appear that the presence of water weeds and the competition of water bacteria may offer obstacles to the vitality of anthrax bicilli iv water.