The Birmingham age-herald., 1919-02-16

London, January le.-(Special Corre
 spondence.) )-Learned mathematicians discourse obscurely on the fourth dl
 mension; and nobody takes much notice of them But with the coming of avia- tfon the world has suddenly awakened to the fact that the third dimension, of which we all learn a little and forget good deal more, has become a factor
 which to a large extent governs the life and safety of almost all the Euro pean nations.
 For the question of height is one of supreme importance in aerial warfare; and on the solution of the various prob
 lems connected with it depended the
 success or failure of the blows that
 the, allies struck at Germany from above, and the effectiveness of the de lenses which were planned to repel the air forces who attacked Great Britain.
 Many people are unaware of the fac,
 tor, that determinesrthe height reached
 by aircraft. Rarity of the atmospheric air is the factor. The higher one goes
 the thinner becomes the air, until at about 25,000 feet (nearly five miles) it is so rarefed that there is hardly suf- ncient body" in it to support the
 planes of an airplane. For it must be remembered that, although it is invisi- ble, air supports flying machine in almost the same way as water buoys up a ship. No contrivance could be main tained aloft in a vacuum
 The greatest altitude to which ma chine can ascend is termed it's "ab- solute ceiling and it is significant to note, so great are the difficulties to be
 overcome in the upper regions that no higher flights have been made since the commencement of the war with a few trifling exceptions than were car l ried out in the summer of 1914. (This was written just before the six-mile high flight) A5t
 The records for altitude were held for long time by German pilots, and
 remaiped unbeaten until comparative l ly recently. Mere altitude alone, how | ever, is of little importance in air | warfare. What is wanted is fast rate
 of climb, and it is in this direction that
 the most remarkable developments have l taken place. t4 -. - 1 An airplane that could ascend to 30,- 900 feet would possess but small mili-
 tary value if it were going to take all day doing so. II would not be nearly so useful as machine capable of ris- I ing only to 10000 feet but of doing l it in half the time. This argument ! however only holds good within certain limits Most aerial work over the lines
 was carried out towards the end of the
 war at a height of round about 15,-
 0O0---as compared to 5000 feet at the be- <, ginning of the war-because at this al titude an aircraft although not actu- ] ally out of range of anti-aircraft gun I fire, is an exceedingly difficult target Every service machine most. therefore l be able to make at least this height as a first consideration.
 | As almost any modern machine can put
 up reasonably good performance up to 1c,C00 feet, it is between the heights oi 10000 and 10000 that climbing mower is
 most vitally needed, and proves most 1 effective. A machine which goes up like
 a rocket to 5000 feet in three minutes,
 but takes IS minutes to get to 15,00o feet
 is not so useful as one that, though
 climbing slower at the start, has a stead 1 fer average and makes, 15.000 feet in 1s l minutes. And here we come to quite