PROF. ROTCH ON AERONAUTICS

Professor A. Lawrence Rotch h.'91, of the department of Geology, delivered a lecture on "The Route of the Air" in the Union yesterday evening, giving a general discussion of aerial navigation.

Professor Rotch stated that the theory of aero dynamics was important enough to attract the attention of the colleges, and that courses in the subject should be established. Several colleges already have courses in the study of the air and the machines used in its navigation. The time will soon come when all universities will have similar courses.

International Movement.

The aeronautical movement has an international organization which is interesting because it is voluntary. The headquarters are in Germany and each station in the various nations is daily informed of all aeronautical news.

Professor Rotch then pointed out the difference between ocean navigation and air navigation, and the difficulties encountered in the latter. The aeroplane and the balloon can make no headway against a wind unless their velocity is greater.

Difficulties With Air Currents.

The aviator has a vast number of varying air currents to contend with, and he must therefore be acquainted with relative velocities and varying conditions of winds. To illustrate these conditions Professor Rotch showed charts on the screen of wind velocity and pressure at low and high altitudes. The pressure and velocity increase rapidly as the altitude increases. Charts were also shown of the prevalent winds. West winds are prevalent at high altitudes and in the winter. North of the equator the trade winds are northeasterly and south of the equator they are southeasterly. If the aviator or balloonist followed a northeasterly wind to the west, and then suddenly ascended to a high altitude, he would be carried back to the east again. Although there are charts of various air routes, no practical application of them has yet been made.

The subject of the lecture "The Route of the Air" was prompted by the thought of Dr. Jeffries '73, who was the first man who crossed from England to France by route of the air in 1885. Professor Rotch said that the practical application of air routes and machines for their navigation would soon be made.