SCIENCE NOTES.

Otago Witness, Issue 3274, 13 December 1916, Page 55

SCIENCE NOTES.

A Petrol Substitute. — A promising substitute for petrol in some localities seems to be natalite, a_ distillate from molasses that a South African company has arranged to supply at the rate of 6000 gallons per day. In a reported 500-milo test with a 22 horse-power car weighing about 36001 b, it gave an average of 16.4 miles, or 26.2 ton miles, per gallon. The corrosive acids from the burning of this rr.otor spirit were neutralised during combustion by ineans*"*of an alkali. Noiseless Car Wheels A noiseless car wheel has been designed by Mr Edwin G. Madden, an American. It is asserted to have a number of important advantages over the old-fashioned wheel. It consists of two wheels, one within the other, and separated from each other by moans of a rubber filling. The •combination takes up all vibration and shock, so that the noise is reduced to almost nothing. Some of these wheels have been in use on a train line for nearly a year, and the degree of success which has. attended their use has resulted in declaring the invention a success. Pure Iron Almost Unknown.— Iron is the one metal of the few in common use with which wo might be supposed to be fairly familiar. Yet iron even approximately pure is a groat rarity in nature, chiefly known from a very small quantity of native iron found in Greenland, and iron of a high degree of purity is so rare even in the chemist's laboratory that its properties are not yet fully determined. Giving an account of the work of the U.S. Bureau of Standards, Dr Geo. K. .Burgess states that the preparation of iron of a purity of 99.7 per cent, was found by no means a simple matter. Iron deposited from an electrolytic bath was used as the starting-point. But this can be broken jn the hands, is cellular, and contains hydrogen, so it had to be molted in a vacuum to expel this and other gases. To avoid contamination by silica, from the best crucibles on the market, it was necessary to devise methods for preparing speciallypurified and calcined magnesia. This was made into the crucibles used for melting. Even this purification, the iron, which nas become indeed a precious metal, is not entirely free from oxygon, and tho amount of this impurity has not been exactly determined. The few grams of socalled pure iron, however, has been distributed among eminent chemists for more careful study than this metal has hitherto received.

Why Some Seeds Fail.—

Old seeds may fail because the conditions most favourable for fresh seeds are no longer suitable. In experiments reported to the Paris Academy of Sciences by M. Demoussy, cress seed seven years old did not germinate in distilled water at the ordinarily favourable temperature of 80dcg F.; but 40 per cent, sprouted within 10 days in a 25 per cent, solution of hydrogen peroxide, and 25 per cent, within 15 days In pure water when the temperature was kept at sQdcg to 57deg. These curious results proved to be associated with the development of parasitic germs. Fresh seeds sprout before the microbes get a start; but the old seeds germinate more slowly, and with ordinary warmth the parasitic life develops so much quicker that the seeds arc smothered, and rot from lack of oxygen. The hydrogen peroxide, or oxygenated water, aids the seeds both by destroying the micro-organisms and by supplying oxygen. The low temperature acts favourably by retarding the microbe development several days, and thus giving the germinating seeds an earlier start. A considerable percentage of seeds rejected in the maltbouse from a study of gcrminative power would grow when sown by the farmer, because tho conditions of aeration and temperature would be more suitable.