NATURE 



[March 6, 1919 



tioned, the staff of the Meteorological Office was 

 small, and outside it there were very few expert 

 meteorologists who were available. At first three of 

 the senior staff of the Meteorological OtTfice received 

 commissions for duty in France, and afterwards a 

 number of men who had a thoroughly scientific educa- 

 tion at a university joined the Meteorological Office 

 for longer or shorter periods of training before being 

 posted to the Meteorological Section, and in this way 

 a high-grade scientific staff was formed and main- 

 tained. To a training which included especially 

 rnathematics and physics was added as much instruc- 

 tion and practice in advanced meteorology as could 

 be given in the time available, and on the basis of 

 such an education the meteorological aspect of the 

 problems was quickly appreciated. 



As time went on the scope and number of such 

 reports and warnings steadily increased until there 

 was a regular and continuous flow of information 

 sent out from meteorological offices to various 

 branches of the Service for them to utilise as best 

 fitted the operations in hand. The Royal Air Force 

 required forecasts of weather for short periods which 

 it could use for its reconnoitring and bombing 

 squadrons ; for day operations reports of the wind 

 direction and velocity obtained from pilot-balloon 

 ascents and high-angle shell-bursts were communi- 

 cated from different altitudes up to 20,000 ft. ; for 

 night operations information for lower levels sufficed, 

 and the arrangements had to be modified. For high 

 altitudes a central station could supply information 

 adequately, but when data concerning lower levels 

 became important, where the air turbulence set up by 

 friction with the earth's surface became a material 

 factor, the reports were more effectively supplied by 

 local stations where the special conditions could be 

 more effectively studied. For all this the most rapid 

 means of transmission is essential ; for the shorter the 

 forecast period, and the more detailed the forecast in 

 its information, the more rapidly must it be placed 

 at the disposal of the aviator if it is not to mislead 

 him. These reports were largely supplemented by tele- 

 phone inquiries by those interested, and a precision 

 was demanded which was often very difficult, and 

 sometimes impossible, to attain. Success in answer- 

 ing these inquiries is reached by having as meteoro- 

 logical officers men who have an acquaintance with 

 the physical condition of the region, and also pos- 

 sess such a scientific training that they instinctively 

 proceed from cause to effect, and facts at once fall 

 into their place in their minds. This is very different 

 from the acquired skill of an empirical forecaster, who 

 can never attain the same confidence in his opinion. 

 The work of a meteorological officer who has to advise 

 on the suitability of conditions for long flights, 

 especially on active service, is very responsible, and 

 throws a great strain on him, since he cannot but 

 feel that on his advice great risks may be taken and 

 grave danger encountered. In regions where high 

 plateaux exist near the sea-coast, as in Macedonia, 

 the cold-air currents which stream downwards, by 

 reason of their greater density, to lower levels often 

 attain full-gale velocity, blowing in violent gusts, and 

 constitute an element of serious danger to aviators. 

 The conditions which favour such a phenomenon are 

 known and recognisable, but it may be very difficult 

 to sav precisely whether or not the descent of cold 

 air will take this violent form. 



In chemical warfare a different set of problems was 

 encountered. Here we are concerned with the move- 

 ment of air-currents close to the surface of the 

 ground, affected by all its irregularities, diverted thi,s 

 wav and that by obstacles, and generally in that state 

 of irregular motion known as turbulence in which 

 eddies form, break up, and re-form, greatly com- 

 NO. 2575, VOL. 103] 



phcatmg the conditions. At night, too, when the sur- 

 face wind may die down to a calm and the ground 

 cools under a clear sky, the colder and heavier air 

 streams down from higher ridges into valleys and low- 

 ground. Consequently the direction and velocity of 

 air-currents along the front had constantly to be 

 observed and studied in relation to the relief and 

 conditions of each section; so long as the wind was 

 favourable for enemy operations, or even likely to 

 shift into a favourable quarter, observations, reports, 

 and warnings were unceasingly needed. 



But, besides the aviators, there are other branches 

 which are vitally interested in the conditions which 

 prevail in the upper air. Projectiles leave the firing- 

 point and traverse a considerable thickness of the 

 atmosphere during their flight, reaching an altitude 

 of about 10,000 ft. for a fifty-second trajectory. In its 

 passage through the air a projectile traverses strata of 

 different temperatures, and consequently of various 

 densities, so that a correction has to be applied to the 

 range-tables. On a winter day, when the temperature 

 at the surface is 3° F., the temperature at 3000 ft., 

 6000 ft., and 9000 ft. may be 15° F., 16° F., and 

 12° F. respectively, so that any correction based on the 

 temperature near the ground would be wrong. Also 

 the wind varies considerably, and often irregularly, 

 both in velocity and direction as the ground is left, so 

 that a correction based on mean conditions here will 

 probably be widely different from that which should 

 be used on any particular occasion. '' 



These considerations led to a much wider applica- 

 tion of meteorological information to the practical 

 correction of gunnery than had hitherto been em- 

 ployed, and reports of upper-air temperature and of 

 the velocity and direction of the wind at various alti- 

 tudes were regularly prepared and transmitted from 

 meteorological stations along the various fronts. This 

 increased application of meteorology to ballistics raises 

 many problems of interest and importance, which 

 demand for their solution the co-operation of scientific 

 gunnery and meteorological science of the highest 

 order. 



To mention another field, the sound-waves which 

 are recorded in sound-ranging, that wonderful adapta- 

 tion of the physical instruments of the laboratory to 

 practical use on the field of battle, traverse the lower 

 layers of the atmosphere, and as higher and higher 

 accuracy was aimed at, it became clear that meteoro- 

 logical observation must be made concurrently, and 

 utilised in order to attain the desired precision. 



Frequent mention was made during the war 

 of the meteorological efficiency of the enemy's 

 organisation and of the very favourable conditions 

 which he experienced during many of his operations ; 

 his superiority in these directions was not infre- 

 quently assumed. It is not possible to compare the 

 effectiveness and success of the rival organisations 

 until much more information is available and, in the 

 discussion and investigation of past operations, the 

 various contributing factors have been sorted out and 

 duly weighed. No doubt Germany started with a 

 much larger number of men who had received a 

 scientific training in the subject, for professors of 

 meteorology existed at several universities ; the appre- 

 ciation of the subject and its practical value, too, 

 may have been more general among that nation ; but, 

 as a personal opinion, I do not believe that it 

 attained a higher standard than our own. Many 

 apparently did not realise that the occurrence of bad 

 weather during operations did not necessarily mean 

 that the commander and his staff had no information 

 regarding the impending weather changes ; but 

 weather Is onlv one of many factors which have to 

 be taken Into consideration, and It must often be 



