PRESENT PROBLEMS OF METEOROLOGY 743 



might be acquired at heights far greater than those to which a human 

 being can hope to ascend and live. 1 The use of the so-called ballons- 

 sondes, liberated and abandoned to their fate with the expectation 

 that when they fall to the ground the records will be recovered, was 

 soon adopted in Germany, and has since spread all over Europe. It 

 has been introduced into the United States by the writer, who has 

 just dispatched the first of these registration-balloons from St. Louis, 

 hoping in this way to obtain the temperatures at heights never before 

 reached above the American continent. 2 



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 meteorological elements in the free air, 3 and this me- 

 thod of observation, which presents the great advantage of securing 

 the data in the different atmospheric strata almost simultaneously 

 and nearly vertically above the station on the ground, has been exten- 

 sively 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, 4 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 automatically the values 

 of temperature, moisture, and wind with a precision comparable to the 

 eye-readings of standard instruments by a good observer. 



Having examined 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 independent of 

 another, and, consequently, a weather-map of the whole globe, day by 

 day, is of prime importance. Were this provided, the atmospheric 

 changes occurring simultaneously in both hemispheres could be 

 watched and their relation to what have been called " the great centres 

 of action " investigated. 5 Thanks to the increasing 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 gradually coming into 

 view. 



1 Nature, vol. XLVIII, pp. 160-161. 



2 Science, N. S., vol. xxi, pp. 76-77. 



3 Quarterlij Journal of Royal Meteorological Society, vol. xxiv, pp. 250-259. 



4 Ibid vol. xxvin, pp. 1-16. 



5 Report of International Meteorological Committee, St. Petersburg, 1899, 

 Appendix xi. 



