SCIENCE OF THE DAY.

New Zealand Herald, Volume LXVII, Issue 20514, 15 March 1930, Page 5 (Supplement)

SCIENCE OF THE DAY.

MYSTERIES OF ASTRONOMY.

One-third of the major mysteries of astronomy may be solved by the 200 in. telescopo which is at present under construction in California, said Dr. Harlow Shapley, director of Harvard Observatory, in a recent lecture to the American Philosophical Society. According to present plans, the mirror of the telescope will be made, not of glass, but of fused quartz, a substance which expands very little 'in heating. This property is important, because so largo a mass would not expand evenly, and a change of temperature would, therefore, result in some loss in the sharpness of the image. The construction of so largo a mirror is ' inevitably experimental, but it is understood that the method has been successful in the case of smaller models.

Giving a list of tho ten chief problems of astronomy, Dr. Shapley said that onethird of them might be solved by mathematical analysis, and one-third by telescopes of moderate power; but for the remainder, telescopes of the 200 in. calibre or greater would bo necessary. The nucleus of the galactic universe of stars was hopelessly hidden, ho said, behind dark clouds of matter far out in the direction of Sagittarius. From these distant regions of the universe no light penetrated to the earth, but their gravitational effects could bo discerned by measuring the motions of stars, which were too distant for the present Mount Wilson telescope. The irregularities in the rotation of the earth constitute one of the most interesting of outstanding problems. "At present," Dr. Shapley continued, " we cannot prophesy the future positions of the I poles. If Commander Byrd hit the exact South Pole with the American flag, tho polo will soon move away, and give another observer a chance. In any case, the probability is that sooner or later the flag and tho polo will coincide." Among the other problems which Dr. Shapley enumerated are the birthplaces of comets, the number of dwarf stars, the running away of external galaxies, and tho bounds of the universe.

USES OF BAKELITE. The curious name of Bakclite suggests firing operations, but it is an artificial resiii, whose inventor is one Baekeland. It is made by " the reaction of phenol and formaldehyde in the presence of suitablo catalysts. The resin so produced looks like amber, but it is much harder; it can be sawn or drilled or turned. Also it can bo coloured to resemble ivory, tortoishell, mother-of-pearl, ebony, or polished hardwood. Bakelite is remarkably useful to electricians because it is a splendid non-conductor; and as it is not inflammablo, is insoluble in water, and remains unchanged by corrosive gases; it is valuable not only for ornaments but in the chemical trades. It has been used for beads, buttons, umbrella handles, knifo handles, brush handles and combs. Thousands of tons are now made every year, and new uses are being constantly found for it.

FIRE ON AIRCRAFT. " Flamo traps," to prevent the spread of firo in mixtures of gas and air, such as are found in airships, are described in a report of tho Aeronautical Research Committee. The report deals with a series of experiments carried out by Squadron Leader W. Helmore at the Cambridge University Engineering Laboratory. Tho object was to examine the means of extinguishing flame in combustible gaseous mixtures with a view to increasing their safety in use in aircraft. _ It was found that flamo could bo effectively extinguished by the provision of suitably dimensioned cooling surfaces. Byvpniploying batteries of parallel tubes, like radiators, traps wcro formed which would arrest the passage of tho flame in hydrogen, oil gas and petrol-air mixtures. The cooling surfaces, the report states, need not tako tho form of tubes. They can be mado of corrugated sheets alternating i with flat sheets of metal.