Januaey 10, 1902.] 



SCIENCE. 



73 



and velocity of the wind on the ship or at the 

 kite, as well as the speed of the ship, the tri- 

 angle of forces gave the true velocity of the 

 wind and its direction relative to the course of 



the vessel. For example, let ^B be the wind 

 due to the motion of the steamer in the oppo- 

 site direction and let AC be the wind observed 

 on board, the direction relative to the vessel 

 being indicated by the drift of the smoke and 

 its velocity measured by an anemometer. Then 

 the third side, BG, of the triangle represents 

 the direction of the natural wind and its 

 velocity on the same scale. The problem is not 

 new, for in Abbe's 'Treatise on Meteorological 

 Apparatus and Methods' {Report of the Chief 

 Signal Officer for 1887, Part 2), several graph- 

 ical and mathematical solutions that have been 

 proposed since 1847 are cited, and in the No- 

 vember Pilot Chart of the United States Hydro- 

 graphic Office, a table shows the true direction 

 of the wind with regard to the ship and its 

 force, when there are known, the speed of the 

 ship, the angle that the apparent wind makes 

 with it (points off the bow) and the force of 

 this wind. 



It does not seem to he understood, however, 

 that the same result may be reached without 

 any measurement whatever of wind velocity 

 or estimation of force by merely measuring, 

 in addition, the angle that the true wind 

 makes with the ship, which is easily done by 

 watching from the weather side the wave- 

 crests as they approach the vessel. If, in the 

 figure, AB again represent in direction and 

 speed the ship's wind, and AC, in direction 

 only, the resultant wind, then by measuring 

 the angle DBA that the true wind makes with 

 the ship we have, as before, the third side, BC, 

 of the triangle. The method fails when the 

 wind is in line with the ship's course and be- 

 comes inaccurate when the angle between 

 them is small. In other cases, since the speed 



and course of the ship are always sufficientl,y 

 known and the two angles BAC and DBA can 

 be measured with precision, the method is bet- 

 ter than the first because of the difficulty in 

 measuring the resultant velocity, arising from 

 the upward deflection of the wind on striking 

 the ship. When steaming through calm air, 

 experiments with Dines' portable pressure 

 anemometer demonstrated that in few locali- 

 ties on boai'd was the speed of the vessel indi- 

 cated by the horizontal movement of the air, 

 one such place being just aft of the bow. Else- 

 where a less speed was usually recorded, 

 though under the bridge the comijressed vein 

 of air flowed astern faster than the boat moved 

 ahead. In view of this difiiculty of measuring 

 the apparent wind velocity on a moving ves- 

 sel, any method of ascertaining the true 

 velocity with considerable accuracy, without 

 employing an anemometer, is desirable from 

 a scientific as well as from a practical stand- 

 point, and, therefore, the simple method last 

 described, which may usually replace the 

 other, is now published for the first time, so 

 far as the writer is aware. 



A. Lawrence Eotch. 

 Blue Hill Meteoeological 



Observatory, December 10, 1901. 



THE ANDREW CARNEGIE RESEARCH SCHOLARSHIP. 



A RESEARCH scholarship or scholarships, of 

 such value as many appear expedient to the 

 Council of the Iron and Steel Institute, from 

 time to time founded by Mr. Andrew Car- 

 negie (Vice-President), who has presented to 

 the Iron and Steel Institute sixty-four one- 

 thousand dollar Pittsburg, Bessemer and Lake 

 Erie Railroad Company 5 per cent. Debenture 

 bonds for the purpose, will be awarded an- 

 nually, irrespective of sex or nationality, on 

 the recommendation of the council of the 

 institute. Candidates, who must be under 

 thirty-five years of age, must apply, on a 

 special form before the end of March to the 

 secretary of the institute. 



The object of this scheme of scholarships 

 is not to facilitate ordinary collegiate studies, 

 but to enable students, who have passed 

 through college curriculum or have been 

 trained in industrial establishments, to con- 



