SCIENCE NOTES.

Otago Witness, Issue 3102, 27 August 1913, Page 68

SCIENCE NOTES.

A Record Spring Test.— During the course of some tests of locomotive spring steel made of vanadium steel a fibre strength of 256.0001 b per square inch as the elastic limit was developed. Tjns, as far as our knowledge goes, constitutes a record for locomotive spring steel. Carbon, oil-tempered springs showed an elastic limit of 101,0001 b; chrome-nickel, 12 Ji 1 c1 0m P 01 ' 0 J springs, an elastic limit of 104,500ib; and the chromo-vanadium oiltemprred springs showed a limit of 256,000ib. Fish Preserved Without Ice.— Professor Alexander Danilctsky, a Russian scientist, claims to have discovered a now process for preserving fish. Before a recent invitat.on luncheon was eaten the guests saw 14 old fish in glass jars, immersed in a liquid which is the professor s special preparation. The fish were then taken out of the jars, and the guests saw them cooked and afterwards ate them. The fish had been scaled up in glass jars in the presence of impartial witnesses. Pro-, fessor Danilevsky claims by his method to keep fish fresh lor as long as three weeks or a month. He also has a process by which ho can keep fish in jars for two years, and they will still bo thoroughly pure and eatable. Glow-worms.— Consider the glow-worm of the field, how it glows, was the moral inculcated by M. Daniel Berthelot in his presidential address before the National Society of Electricians, lor the giow-worm, it appears, as a machine for the production of light is perfection itself. It has tha sun, in the words of exPrcsident Roosevelt, beaten to a pitiable frazzle. As to gas and electric light, one is almost ashamed to mention them in the same sentence—such is their criminal waste of energy in producing heat when only light is required of them. Here are the humiliating figures:—Gas, 1.2 per cent, on every 100 units of energy expended, electric light 1.5, the sun 14 per cent., and the glow-worm, with its cold, dry light, 100 per cent. This admirable result, the lecturer explained, the glow-worm produced by an “ electro-capillary apparatus, constituted by thousands of cells. Future systems of lighting should, it follows, take the glow-worm as their model. Rook Paintings in Tunis. —

Rock-paintings of an interesting kind in the south region of Tunis are described by M. Henri Roux and published in the Revue Tunisienne. One of these was noticed on a rock wall in the Djehcl Bliji, and it represents very likely a combat of men in conventional drawing and animals which it is difficult to identify. The age of this painting raises quite a controversy among scientists, and some think that it is contemporary with the Berber civilisation —that is, intermediate between the Stone Age and the ago of metals. According to this idea it belongs in the last part of the neolithicperiod. Biit M Roux wishes to place it at a more ancient epoch and class it in the middle or first part of the neolithic period, it being due to a civilisation which is more ancient than the Berbers, and M. Gobert also thinks that it is the work of negroid people to whom are due the flints of the neolithic ago found in North Africa. Beautiful Colour Effects.—

The electrolysis of lead salts (says the Scientific American) produces peroxide of loud at the anode, and if deposited in films of varying thickness on polished plates beautiful colour effects are obtained. Oassiot’s process involved the electrolysis of load acetate and an anode of a highly-polished steel plate. This was laid on the bottom of a basin and covered with a cardboard perforated or cut out in some design. On this was placed a copper cathode and a current from two or throe colls run for 10 or 20 minutes. The film of lead peroxide on the anode or steel plate displayed the most exquisite tints of the rainbow, duo to the light reflected through the film from the polished steel beneath. The tints vary in reflected and transmitted light, and are best seen at a window when a shoot of white paper ia inclined over the plate. Professor Walter Maunder, the eminent astronomer, has revived the speculation as to whether the heavenly bodies are inhabited or not by publishing some careful calculations as to their temperature. Ho shows that the sun s temperature is more than 5000 C., while the moon, -owing to its lack of atmosphere, is at night about the temperature of liquid air. Mercury, which always turns one face to the sun, must bo far' hotter than anything of which wo have any knowledge, while Mars must alwavs be below freezing-point. The more distant planets—Jupiter, Saturn, Uranus, and Neptune—are so far away from the sun that they receive scarcely any heat from him, while' they are still in a nearly incandescent condition, and, according to Professor Maunder, have probably no solid nucleus. Venus, however, has a moan temperature of 69deg 0., and at the Equator one of 95dog C., so that, allowing for the difference in nressnro, water should boil at its equator. This would send forth such vast quantities of steam that the clouds would cut off much of the sun’s heat. Our authority denies that any planet but Venus can be habitable, and as to Venus he reserves judgment. For protipJasm, the universal constituent of all living matter, cannot live permanently below Odeg C. nor above lOOdog C. Therefore the sun, Mercury, and the distant planets would be too

hot for it, while Mars and the moon wou'd bo too cold, leaving only Venus as a possibility. Rod Light as Milk Preservative. — Interesting experiments have recently been made concerning the influence of red light on milk. That light as such is detrimental to the conservation of milk has long been known, but which of the rays really did the mischief has only now been determined, when it was found that the red rays are beneficial, while those toward the violet side of the spectrum caused the miik to “ turn.” Pure, fresh milk placed in an uncolonred glass bottle in the full sunlight, and sterilised and pasteurised milk, placed also in uncoloured bottles in the same place, were found at the end of the day to bo completely spoiled and unfit for consumption. Absolutely no difference could be detected between the ordinary “ fresh ” milk and that which had been sterilised—both were equally bad. - But if unsterilised milk is placed in a red bottle or in a bottle wrapped in red paper in the full sunlight it keeps perfectly good for 10 hours. In Holland much care is being expended on delivering milk to the public. The “ fresh milk ” is brought around by the milkmen in large covered brass vessels placed on small hand-carts. On these same hand-carts are open holders to contain the bottles of pasteurised or sterilised milk, which costs rather more, but to which many people give the preference, as it is considered more hygienic. Now, however, that experiments have proved how easily oven this pure, sterilised product “turns” by the influence of the light, it may soon bo expected that every dairy will adopt red bottle's. Until u sufficient quantity of such shall have been manufactured, tbe bottles will be wrapped in rod paper. Electrical Stimulation of Plant Growth.—

The question of increasing the growth of plants by applying electricity in various ways is one which is being discussed at present. One of the principal workers in this direction in Trance is Lieutenant Basty, and (says the Scientific American) ho is now engaged in making some very interesting experiments upon the growth of crops. The excellent results which ho obtained have attracted the attention of the Agricultural Department, and the Minister is now having the matter taken up from a scientific standpoint. Lieutenant Basty is now proceeding in his experiments, upon the basis that the atmosphere is £ii inexhaustible source of electricity, and on the other hand physiologists assert that the electrical effect serves to hasten and also to regularise the circulation of liquids in the capillary tubes, such as those of plants. If wo cause electricity to act on the stalks or roots of a plant, the circulation of sap is stimulated and made more rapid and the assimilation better carried out, hence the production from the plant will be more abundant. This idea seems to be borne out by an actual increase in the amount of crops which the author finds. He collects atmospheric electricity by small lightning rods which consist of simple iron rods ending in a non-rusting point. For vegetable gardens the rods should bo about 3ft high, but for field crops, such as wheat and other cereals, hemp and the like, the rods should have 6ft height. The diameters are from gin to iin, and the rods are driven into the ground Bin or lOin, according to the length of the roots of the plants. It is found that tho action is exerted on a radius on the surface of the ground equal to the height of the rod. In practice, tho cost of such rods and the labour in mounting them is very small. The following figures for the -increase in the growth of certain crops may seem surprising, but they are given on good authority. For potatoes, instead of 1001 b, as before, ho now obtains 1731 b. Beets show 1661 b. Hemp, for tho stalk, 3221 b, against 1001 b in all those cases.