874 



SCIENCE. 



[N. S. Vol. XX. No. 521. 



all over Europe. It has been introduced 

 into the United States by the writer, who 

 iias just despatched the first of these 

 a-egistration-balloons from St. Louis, hop- 

 ing in this way to obtain the temperatures 

 at heights never before reached above the 

 American continent. 



In 1894, at the Blue Hill Observatory, 

 near Boston, kites were first used to lift 

 self-recording instruments and so obtain 

 graphical records of the various meteoro- 

 logical elements in the free air, and this 

 method of obseiwation, which presents the 

 great advantage of securing the data in the 

 different atmospheric strata almost simul- 

 taneotisly and nearly vertically above the 

 station on the ground, has been extensively 

 employed both in this country and abroad. 

 Heights exceeding three miles have .been 

 attained and it is possible to ascend a mile 

 or two on almost any day when there is 

 wind. To render the method independent 

 of this factor, the plan of flying kites from 

 a steamship was introduced by the writer 

 three years ago, and this scheme, too, is now 

 being successfully employed in Europe. 

 The exploration of the free air by balloons 

 and kites, it may be remarked, has given 

 rise to the construction of special types of 

 light and simple self-recording instruments, 

 which are capable of recording automat- 

 ically the values of temperature, moisture 

 and wind with a precision comparable to 

 the eye-readings of standard instruments 

 by a good observer. 



Having described some of the newer 

 methods of meteorological investigation, let 

 us now consider how they may help to solve 

 certain problems in dynamic meteorology. 

 It should be premised that, since the 

 atmosphere is relatively a thin layer with 

 respect to the globe which it covers, no 

 portion of it can be regarded as independ- 

 ent of another and, consequently, a 

 weather-map of the whole globe, day by 

 day, is of prime importance. "Were this 



provided, the atmospheric changes occur- 

 ring simultaneously in both hemispheres 

 could be watched and their relation to what 

 have been called ' the great centers of ac- 

 tion, ' investigated. Thanks to the increas- 

 ing area covered by reports from the 

 various weather services, the unmapped 

 surface of the globe is being diminished, so 

 that a complete picture of the state of the 

 atmosphere each day over the land is grad- 

 ually coming into view. 



The mathematical application of the 

 theory of a rotating sphere, surrounded 

 by a heated atmosphere, to explain the 

 circulation of the atmosphere as we find it, 

 has not been satisfactory, owing to our 

 lack of knowledge of the conditions of the 

 upper air, as well as our ignorance con- 

 cerning the physical i^roperties of the at- 

 mosphere itself. To acquire the latter 

 knowledge, research laboratories must be 

 established at selected points, at both high 

 and low levels, and as subjects of study 

 there may be mentioned the determination 

 of the amount of heat received from the 

 sun and its secular variation, if any, the 

 radiating and absorbing power of the air, 

 the relation of pressure, density and tem- 

 perature, the chemical composition of the 

 air, its ionization and radioactivity, and 

 other investigations which have been pro- 

 posed by Professors Abbe and McAdie in 

 their pleas for the creation of such aero- 

 physical laboratories. The observatory 

 now under construction by the United 

 States "Weather Bureau on a mountain in 

 Virginia will, it is hoped, enable some of 

 these problems to receive the attention 

 which they deserve. 



The average circulation of the lower 

 atmosphere is now well known, by reason 

 of the monumental work of Lieutenant 

 Maury on the Avinds over the oceans, and 

 from the mass of data since collected over 

 oceans and continents through the meteoro- 

 logical organizations of the various coun- 



