RANDOM NOTES

Dominion, Volume 29, Issue 185, 4 May 1936, Page 8

RANDOM NOTES

Sidelights on Current Events (By Kickshaws.) The sap, declares a tree expert, is an indication of vigour in all trees. Except. of course, trees. A writer says it is inexplicable why the song “Tell Mother I’ll be There” has lost its popularity. Pe'rhaps the reason is because if you tell a modern mother you'll be there, there is no guessing where she will be herself. ¥ * » A statistician has discovered that there are always a lot of Williams in the House of Commons. Considering the Bills thrown out every session this is all the more surprising. ♦ » • “How is so-called Liberia in Africa getting on? Is it not time some energetic country like Germany was allowed to develop It?” asks “R.H-F.” # » » No doubb residents in the Wellington area fully appreciated on Saturday the force behind a wind blowing at anything from 60 to 85 miles an hour. The gentle manner in which a zephyr caresses the countryside, and the waters, always seems out of proportion to the slap that gales can deliver. It should be realised, however, that the force behind a wind does not increase in proportion to the speed of the wind, but as the square of the wind's speed. Winds up to 10 miles an hour might lie classified as zephyrs. Winds of 20 miles an hour are getting on for half a gale. The force behind the 20-mi le-an-hour wind is four times that of the 10-miles-an-liour wind. The force behind a 40-miles-an-hour wind is again four times that of 20 miles an hour. A 40-mile-an-hour wind has something like 16 times the kick of a 10-mile an hour. A wind of 80 miles an hour has 64 times the kick. This perhaps explains why strong winds seem to be able to shift things, whereas light breezes fail to give any impression of power. • » « As wind speeds go, we in the Welling ton area, and for that matter in other parte of New Zealand, cannot complain. We do have winds tip to 85 miles an hour, but that is about the highest wind speed recorded. Usually the highest recorded gusts in gales do not get ranch above 70 miles an hour. High as these winds appear to be, the fact remains thai higher figures have been recorded in other countries. Even England has known winds of over 100 miles an hour. Speeds of nearly 110 miles have been recorded before now. Scientific measurement of wind velocities at a height of 40 feet above the ground shows that winds never blow steadily, A windy day is made up of a succession of gusts and lulls. Thus the astounding velocities recorded on some occasions are only of momentary duration. The average speed of a gale is usually under half that of the gusts that seem so strong. It may come as a surprise to some readers when they realise that usually the average speed for a day of a southerly buster Is under 20 miles an hour. Particularly severe ones record 25 miles an hour.

Although it is believed that gusts of wind in tornadoes sometimes attain speeds of over 200 miles an hour, the highest wind velocity ever measured scientifically is 150 miles an hour. This speed has been registered on two occasions—at Black River, Jamaica, on November 17, 1912, and at the mouth of the Columbia River. Washington, on January 29, 1921. Britain’s record stands at 111 miles an hour at the Scllly Islands on December 6. 1929. The average speed of the wind for an hour in the last case was only 68 miles. A typhoon that killed 1500 people and damaged 400 miles of country u Tokio a year or so ago had a speed of 120 miles an hour. Some idea of the power in a wind of this nature may be had from the fact that it was sufficient to blow down all but concrete structures.® Even this speed has l>een exceeded in America, where unconfirmed measurements registered a speed of -31 miles an hour ar Mount Washington, in Vermont State. It is believed tha even great er wind speeds occur over the wastes of Central Asia. These figures mav not be so impossible as imagined, when it is realised that a month ago winds of 170 miles an hour were observed 30.000 feet above Wellington «ty.

Yarns that waves were observed oil Petone esplanade 30 and 40 feet high should be taken with a grain or two of salt Not even fishermen are capable of misjudging size as are observers of waves. If waves of even 30. feet high broke on the beach at Petone they would wash away the seafront ano many of the bouses. One good reason why no such wave could reach the shore at Petone l 5 that the sea is too shallow. The wave would break haltwav to Soui.es Island. Wave statistics tire difficult to obtain. It has been shown, however, that the greatest size of waves on a really dirty day in the English Channel does not exceed L feet. Off the mouth of the Tyne waves of 40 feet have been recorded. Experts believe that 40 feet marks the usual limit in height of waves. The rougl>e-r bit of ocean In the world, between Cap< Town and Australia, probably stages waves larger than this, but even so it is doubtful if a wind-formed wave unde- the best conditions attains more than a height of 50 feet. A wave when it approaches shallow water increases some 10 to 15 per cent, in height, but p is doubtful if Petone residents saw tniv waves over 10 feet high * * •

Even 10ft. waves are not things to he treated with disrespect The power in a wave of that size has been estimated at five or six horse-power for every foot length of wave. Uiis perhaps explains the ease with which the roads round the harbour were covered several feet in sand and boulders. In fact, boulders almost too heavy to lift were flung several feet on to the roads. As a matter of fact some, very surprising records have been obtained as to the slap of a wave. At Peterhead England, a wave once threw out of position blocks of wall weighing four tons that were 37 feet below low tide mark. The same wave also moved a section of biockwork weighing 3300 tons a distance of two inches. Off Colombo waves attain immetis; force. During the laying of a bretiL water a lencth of sol’d sea wall InO feet by 28 feet was given such a slat’ by a single wave that the whole nib'ed back 15in. in a fraction of a second. An idea of the ability of waveto fling gravel and rocks about may be had from the fact that at Bishop Rock lighthouse. Scilly, gravel was thrown from the sea-bed 156 tinder water to the lighthouse platform 120 feet above sea level, a total height of 270 feet. » * * Ye seek for happiness—ates. the day! Ye find it not in luxury nor in gold. Nor in the fame, nor in the etvied For which. O willing slaves to Custom Severe''task-mistress I ye your hearts -Percy Bysshe Shelley (1792-1S21).