SCIENCE NOTES & NEWS

King Country Chronicle, Volume VII, Issue 554, 29 March 1913, Page 7

SCIENCE NOTES & NEWS

AUTOMATIC LETTER REGIS TRATION. A Paris contemporary gives • description of an automatic mA chine register. The sender of • letter places his fee in the slot, puts his missive in position, and gives two turns with a handle. The letter receives a stamp, presumably not an adhesive, and falls itito the box within the post office. At the same time the sender receives a paper bearing a duplicate number to that which has been impressed on his letter, and this is his receiptThe experiment is only in its initial "stage. LIGHTING LONELY COASTS. For some time past mariners passing along the dangerous coasts of Alaska, having urged the ncessity of establishing lights to assist them in their navigation. But Alaska is a lonely country, and quite unpopulated in many stretches, so that the establishing of an ordinary type of lighthouse is out of the question. The same problem arose in Sweden, but has been ingeniously overcome by resort to an acetylene-gas lighting beacon which will burn without the slightest attention for a period of six months or so. The system is completely successful, and accordingly the United States Government has decided to utilise the same idea on the Alaskan coast. One great feature of this beacon is the sun-valve, whereby the light is ignited and extinguished automatically at varying periods according to the time of year. As day breaks the action of the light causes the acetylene flame to burn low; wheii twilight comes round, the diminishing daylight causes the flame to rise again until it the full lighting efficiency desired for darkness. Bv this means great economy is effected, gas being fully consumed only when the light is required. WAVES TO pRIVE SHIPS. Mr. John Luck, of Brooklyn, has devised a plan to apply wave power to the propulsion of vessels crossing the ocean. The model of his invention, savs "Science Siftings," represents the hull of a vessel equipped with water tanks, fore and aft. In the centre of the craft is a piston rod operated by a series of cogwheels, which furnishes motor power for the ship. Theoretically, lhe weight of water stored in the tanks will be sufficient to put the machinery in motion and move the ship. This force will be applied by rise and fall of the hull, occasioned by the action of the waves. If, for instance, a wave five feet high should strike the vessel astern, tons of force would be thrown upon the operating machinery, which would be simultaneously affected by the suction of the receding waters in other tanks at the opposite end of the boat- It would not, therefore, affect the power of propulsion if the tides were adverse to course of the ship. Rocking of the boat by cross currents would have no effect on the power pressure.

MAN THE MOST PERFECT MACHINE. In the "Scientific American," Dr. J B Hunter offers some interesting comments on Professor Jules Amar's studies on man'as a machine. The result of a large number of

cureful experiments is to show that •the human machine gives a profit of from -'5 to 30.per cent, on the fuel, in other words, the food consumed. In the best artificial machines, the efficiency is only 14 per cent- Thus man is superior to all mechanismsAnd, according to Dr. Hunter, it has been proved that man is "not onlv the greatest psychic entity on earth, but also that his superlative mind is housed in the most capable and serviceable machine that breathes and uses muscle." That is, the human machine is held to be superior to all other animal machines.

Professor Amar's results lead to some practical consideration. He finds, lor example, that a man who eats liberally ought to make up the weight lost by labor in twenty-four hours. If he loses weight this shows that the labor has been excessive, if his weight increases, he has not been doing his maximum amount of work. Professor Amar's experiments show that a man always wastes energy during the first five minutes of work. He also finds that Monday's labor is the worst, and Tuesday's the best, in the week, an interesting effect of the Sunday rest. The moral drawn by Dr. Hunter is that it is unwise, as well as unkind, to overwork the human machine- 9

In answer to the question, Whaf. it fatigue? Professor Amar an* swers that it is the cry of the muscle for more material. When the muscle contracts there is combination of its glycogen with the oxygen of the blood. This becomes a waste pro* duct, a poison which causes the feeling of fatigue, and a fresh sup* ply of glycogen is called for from its store-house, the liver. The in teresting experiment has been tried or injecting into animals extract of fatigued muscle. % The result Is ex treme languor and prostration. When, however, extract of non-fa-tigued muscle is thus injected there is no such effect produced.; 3