Paoxt A Connesronoent, Every branch of science has its struments and apparatus, and {those of the "weather man" are known to most of us.
The "wind. gun'
is the latest acquisition to the lown assemblage of rain-barometer, thermometer lor wind-gauge, Hitherto, observation of wind velocity by the use of cup or press: ture anemometers has been confined chiefly to ground level. Air movements at ground level may, however, be very different from conditions at higher elevations. lst there is or the other, which ever side seems to him to be the more pros Of all the generals he has the best /™®y be strong winds sing. calm at the earth's surface, there
position from both a military" and higher revels, and this is i portant Political "standpoint. "He has ante to the meteorologist and organization. [Practica Geanee to and, of very of Bghting the airman, Anyone who discounts the fighting {The use of pilot balloons, the moveability of Feng Yuchsiang's soldiers ments of which have been observed making a mistake.
Chang Tso-more afraid of them than anyone else in China, otherwise he would have fought them as he did Wang Chen-ping's army. lby optical instruments, hax provid Jed only inadlequade means of obtain ing information of air movements at. Is; in addition to their the important matter of by conditions of visibility—i. low cloud and fog.
Marksmen, in refined target, practice, take precise account of the wind, Jand by the adjustment! of the sights the rifle is tilted towards the wind so that the bullet in its fight may be deflected to the bull. The principle of the wind-gun is the sams Dut the bullet is discharged upwards, ithe bore of the gun is smooth, as a /whizzing bullet would introduce complications of calculation, and, the target is the spot from which the gun is discharged and to which the ball returns after reaching its high-lest point, coming to rest, and ma} ting its return trip. The observer is, jshelteved under steel roof, which protects him from the barrage and [which signals the return of the bul-Jot by a loud ping. Tt need scarcely be added that observations are not /made in densely populated spots, or the weather man would add terror to the annoyance which the layman sometimes associates with weather Iprediction—espocially when It is remembered that the ball reaches the earth with the velocity with which it left the gun.
Standard charges are used for pro-Jjecting bullets to definite heights, larger bullets ave used for estimating the velocity of strong winds, smaller ight winds, and the gun is tilted towards the wind until the ball strikes the steel roof on coming home again. The deftection of the bullet by the wind is effected for the mont part towards the end of the upward flight and the begining of its return—that is, at the point when the ball is near the condition of rest. With suitable corrections the" instrument thus affords method of measuring wind velocity of approximately the range lof the gun for a particular charge, Mr. L. F. Richardson has deduced appropriate equations connecting the time of flight, the angle of deflection lof the gun, and the weight and fof projected sphere, and after the calculations have been made a serian graphs for successively Longe ranges completes the investigation for the different air levels, The highest range attempted so far ix about 800 yards, the time for the return fight being about 25 seconds,
Text read from the printed page and cleaned; old type leaves the occasional error.