NOTES AND COMMENTS.

New Zealand Herald, Volume LIX, Issue 18211, 3 October 1922, Page 6

NOTES AND COMMENTS.

BRITISH AIR POLICY.

Tho alarm and agitation which had arisen during the last six months at our absolute defencelessncss in tho air began toward the end of the session to exerci.se direct pressure on tho Government, says the London Spectator. It was* calculated that to create an air force on our traditional naval one-power basis would soon entail an annual estimate of £100,000.000 a year. Obviously the Government could not face the economy campaign with such a proposal. Hence, inevitably, they compromised, and wo are to have 20 new squadrons at an additional cost of £2,000,000 a year. This will givo us in all 32 squadrons with which to faco tho French establishment of 220 squadrons. The truth is that wo simply cannot afford a mobilised air forco large enough to afford us protection, and that any money spent on the creation of one under that size is simply thrown away. The only possible way of meeting the situation was to stimulate and subsidise civil aviation with every penny that could ho devoted to air defence. This would have given us a flourishing instead of a dead aircraft industry, the one true- training college for pilots—that of practical experience and an active body of researchers, stimulated by the knowledge that practical use would be made of any invention. In fine, what m needed in the present conditions, with aircraft developing and changing with lightning rapidity, with no immediate prospect of war, and with a dominant Navy, perhaps obsolescent, but certainly not obsolete, is not a large and exorbitantly expensive stock of machines which will be themselves worn out and obsolete in 18 months, but the great reservoir 61 knowledge, experience, skill—potential air power—which can alone bo provided by British aircraft flying regularly over the air routes of Europe and the Empire. This is the policy which is pursued by Germany and, in addition to her great military establishment, France. It .will; cost infinitely less than the logical conclusion of the Government's present policy.

ALL-METAL AEROPLANE. People who are concerned about our so-called backwardness in metal aeroplane construction evidently do not know that some of onr work in this direction is a good deal ahead of anything abroad, writes "C. G. Grey, of the Aeroplane. One British firm has approaching completion a big self-protecting bombing machine with two Napier "Lion" engines, which is qutye the last word in this type of work. Practically all the metal aircraft built abroad come out a good deal heavier than similar machines built of wood, whereas this British machine is about 10 per cent, lighter than wooden machines of similar capacity. The popular idea about metal planes is that their chief virtue is imperviousness to fire. As a matter of fact, this point is of no importance whatever, for the danger of fire in the air is not the burning of the aeroplane itself, but the combustion of the petrol in it. The people in the aeroplane are killed by the flaming petrol long before the aeroplane itself catches fire. Hence the advantage of the heavy oil engine which several firms are developing. The real advantage of the all-metal machine is that it is not liable to deteriorate if made of the right sort of metal. And it is the search for this metal that is so intriguing. I believe it has been successful here in England, the home of "stainless" steel—which is the selected material used in the machine above referred to.

FOSSIL PEARLS IN NEW ZEALAND. The occurrence of pearls in a fossil state is recorded in the Journal of Science, by' Mr. J. Marwick, of the geological survey. The first specimen was found by the late Mr. Augustus Hamilton, in the fossiliforous marine clays below the lime* stone at Petano, Hawko's Bay. It is now in the collection of his son, Mr. H. Hamilton, of the Dominion Museum. This pearl, a perfect sphere of two millimetres diameter, is embedded in a piece of the matrix, and although slightly dimmed, is still of good lustre. The second specimen, also from Hawke's Bay, is in the possession of Mr. John Teschma&er, of Green Hill, Mangatahi. Tt was collected by him from the blue sandy clays outcropping on his property in the bed of Okauawa Creek. This example is a great deal larger than the first one, being name five roiliimetree in diameter; it is, however, of somewhat irregular shape and not of good lustre. The pearl was embedded in tho clay directly under a valve of tho large mollusr; Molina, zcalandica Suter. In all probability both gems owe then- origin to this species, for tlii Petane and the Mangatahi clays belong to the same formation of which tho Molina, now extinct, is a characteristic fossili Mr. Marwick adds that many people attribute the origin of pearls to tho oyster; but although several genera of molluscs have provided inferior pearls and pearly structures, the j,roat pearl-producer, Margaritifera, which supplies the bulk of these gems, is not an oyster at all. It" belongs to the family Aviculidae, and it is important to note that in a wide sense Melina zealandica also comes under this family. The formation in which these interesting fossils occur is of Upper or Middle Pliocene age; and, although an exact estimate cannot be made, the length of time that has elapsed since their burial must be in the neighbourhood of three million year*.