NOTES AND COMMENTS.

New Zealand Herald, Volume XLIX, Issue 14895, 22 January 1912, Page 6

NOTES AND COMMENTS.

SOARING" IN AVIATION. ■ The problem of "soaring* with motorless aeroplanes is being . : ardently \ studied by the Wrights and other inventors. ;.-. Dr. A,. F. writing ; in the Scientific American, explains r , that meteorology teaches-that every isolated cumulus and . thunder-head marks the top of an uprising column of hot air. All heated slopes, especially- in the early ,- part of the day, , produce updrafts, particularly if they be long and barren. : Thus the • skill soaring bird finds abundant elevators as he coasts about the atmosphere, -which he may use i to gain sufficient altitude to prolong I his meandering glide ! till- he encounters the . next elevator, whether this be a" vortex or merely an upward deflected wind. Soar- " ing in a truly horizontal wind whose speed , Varies considerably at neighbouring levels, or in different stria* at the same level, is easy to'understand in theory. The bird ' or flier acquires sufficient speed in 'the ' swifter stratum to enable it . to glide into i the lower stratum, there reverse its direction and return in the teeth of the swifter current, to be again caught up and given ; a' new high speed as before. Many ; in-.-• ' stances are reported of such flight in '■■ nature, but none in human art. Actual • performance still challenges \ the skill and [ .cunning of the .practical aviator. . The fact / ; that the wind moves in • neighbouring strata' and stria? is well established, but it '' is still to be proved quantitatively that the > rate of change of speed is quite commonly . sufficient to support prolonged passive , flight. The general theory conceives that the flier faces the direction of the wind, i rises and drifts backward when the wind 1 freshens, sinks and advances during the 1 lull. In a horizontal wind that pulsates in ■ direction merely from side to side, soaring ... may be aided by the. alternate impulses of the air against the flier,. resisted by; its inertia. In a generally horizontal wind ' that undulates up and down, soaring may • be aided in various ways, if not continu- , ously sustained. If the aerial vibrations . be strong and rapid, as in a fluttering I wind, they may exert a sculling action on the wing as a whole or on its flexible rear margin. Such sculling „ action may i occur in wind undulations of considerable • period and amplitude, as where the air follows the contour of the billows in a heaving or tempestuous sea, particularly ' if the flier glide*across the undulations at ' considerable speed, like the albatross, thus ! greatly increasing the apparent frequency y of the rise and fall of the air. In case [ the undulations of the air bo due to a vor- ■ tex rolling about a horizontal axis while advancing with' the.wind, as supposed by r some writers, the bird or glider might re- * main on the ascending side of the vortex - and thus obtain continuous support while ; advancing with the speed of the rolling vortex' whether fast or slow. Such a per- ' formance might eeem marvellous or paradoxical to the witness, since the rolling vortex must be quite invisible/ but the feat would bo no mote remarkable than some reported by aviation experts, who claim to have witnessed the passive flights of aquatic birds for thousands of feet just > oyer the surface of still water in a hardlyperceptible breeze. 5 FRUIT-TREES ON MAIN ROADS. J The matter of planting trees along im- * proved highways has been given little attention in this country, says Engineering 1 (U.S.A.). Massachusetts is the only state - whose highway commission makes a practice of tree planting along State roads. These - trees are set out for the purpose ' of beautifying the road and affording 1 shade. In Germany, roadside trees' not > 1 only, serve the above purposes but they

also serve an economic purpose; as well. In several provinces in that country the i roads are bordered with fruit trees, the J yield of Which ■is applied to the main- i tenance of the roads. In the Province of ] Hanover, alone, there are 7000 miles of i country roads bordered with fruit trees. < The sale of fruit from these trees brings < in no small revenue. At the auction sales j last autumn of native fruit grown on the , trees bordering the country roads in the , township •of "Linden, adjoining the city , of Hanover, the sum of £1000 was secured. i It is ; stated that along certain * stretches , of these roads the yield has amounted to as i much as £120 per mile. During the three or four weeks' period when the fruit , is ripening the roads are patrolled by watchmen on bicycles. It is forbidden to pick up fruit from the ground, and to knock it from the trees is subject to a fine of £5 or more for each offence. The Germans, however, have such respect for laws and regulations for the general good, that cases of theft of fruit from the highway fruit - trees • rarely occur. In other countries, where the average * citizen has his own particular views of the laws of mine and thine, the, planting of fruit trees along State highways might bring little revenue to the State, but nevertheless the plan has economic possibilities which make it worthy of a trial. .THE, BRITISH STRIKES. According to tile Round Table, strikes, like other things,, may be overdone, the general verdict at Home seems to be that the British- strikes have already been a good deal overdone. " For although they have been engaged in sometimes wisely and justifiably, they have also been engaged in frivolously and even absurdly. If they have succeeded conspicuously in . certain cases, it cannot be denied that they have also failed In others. It cannot be denied, however, that the dread of strikes —railway strikes, coal strikes, and others perhaps as well—hangs over us like a cloud. Nor can it bo denied that, though they may bo undertaken very foolishly, and with very little hope of success— though they may be ' directed' (if such a term is appropriate) by men whose love of approbation somewhat outweighs their knowledge of affairs— are not simply . to be brushed aside as utterly preposterous ■■ on this account. They are grounded in something real—in a very grim reality indeed. Agitation \ will usually fail whore there is no actual suffering at the bottom of it. Here, unfortunately, there is very ' real suffering. \ It ia difficult for; people with an income, say, of £5 to £10 a week to understand the difficulties and privations which people with from 18s to 25s a week have to contend against owing to th© rise in the price of food. ' The, extent of ; this rise iB, a matter at ''■ present under investigation. .It is variously computed upon an income of 25s a week at from Is 6dto 2s 6d, as compared with four or five years ago. That there has been a serious rise is not denied. This is the kernel of the matter—'that the value of money wages has fallen, and; that poor people are feeling the pinch."