38o 



NA rURE 



[February 15, 1900 



However, oh getting the kites up, they easily communicated 

 from De Aar to Orange River, over a distance of some seventy 

 miles. I am glad to say that, from later information received, 

 they have been able to obtain poles, which although not quite 

 high enough for long distances are sufficiently useful. We have 

 also sent a number of Major Baden-Powell's kites, which are the 

 only ones I have found to be of real service. 



Stations have been established at Modder River, Enslin, 

 Belmont, Orange River, and De Aar, which work well and 

 will be invaluable in case the field telegraph line connecting 

 these positions should be cut by the enemy. 



It is also satisfactory to note that the military authorities 

 have lately arranged to supply small balloons to my assistants 

 for portable installations on service waggons. 



While I admire the determination of Mr. Bullocke and our 

 assistants in their endeavour to do the very best they could 

 with most imperfect local means, I think it only right to say 

 that if I had been on the spot myself I should have refused to 

 open any station until the officers had provided the means for 

 elevating the wire, which, as you know, is essential to success. 



Mr. Bullocke and another of our assistants in South Africa 

 has been transferred with some of the apparatus to Natal to 

 join General Buller's forces, and it is likely that before the 

 campaign is ended wireless telegraphy will have proved its 

 utility in actual warfare. Two of our assistants bravely volun- 

 teered to take an installation through the Boer lines into 

 Kimberley ; but the milifary authorities did not think fit to 

 grant them permission, as it probably involved too great a risk. 



What the bearing on the campaign would have been if work- 

 ing installations had been established in Ladysmith, Kimberley 

 and Mafeking, before they were besieged, I leave military 

 strategists to state. I am sure you will agree with me that it is 

 much to be regretted that the system could not be got into these 

 towns prior to the commencement of hostilities. 



I find it hard to believe that the Boers possess any workable 

 instruments. Some instruments intended for them were seized 

 by the authorities at Cape Town. These instruments turned 

 out to have been manufactured in Germany. Our assistants, 

 however, found that these instruments were not workable. I 

 need hardly add that as no apparatus has been supplied by us 

 to anyone, the Boers cannot possibly have obtained any of our 

 instruments. 



I have spoken at great length about the things which have 

 been accomplished. I do not like to dwell upon what may, or 

 will, be done in the immediate or more distant future, but there 

 is one thing of which I am confident — viz. that the progress 

 made this year will greatly surpass what has been accomplished 

 during the last twelve months ; and speaking what I believe to 

 be sober sense, I say, that by means of the wireless telegraph, 

 telegrams will be as common, and as much in daily use, on the 

 sea as at present on land. 



THE AIR MOVEMENT AT SIMLA AND IN 



THE WESTERN HIM ALA \AS} 

 "I T will generally be admitted that the Meteorological Reports 

 •*• that are issued from time to time by the Indian authorities 

 possess two very valuable features. The work is thorough in its 

 execution, and the result derived is interesting. The present 

 discussion of the air movement at Simla and in the Western 

 Himalayas does not, in either novelty or importance, fall behind 

 the other niemoirs which have preceded it, although it presents 

 only a portion of the full investigation, which, when complete, 

 will embrace a similar discussion of the observations made at 

 Da:rjeeling, a station as characteristic of the Eastern Himalayas, 

 as Simla is of the Western. Two circumstances contribute to 

 the interest attaching to this special inquiry. One is, that our 

 knowledge of the behaviour of the winds in mountain areas is 

 somewhat limited, both on the practical and theoretical side : 

 consequently, a thorough study is particularly welcome. The 

 other is the suitableness of the situation for such an inquiry, 

 since the phenomena can exhibit themselves here on a large 

 scale, and the influence of minor interfering effects be much 

 eliminated. In Indian meteorology we have to deal with large 



1 "Indian Meteorological Memoirs ; being occasional discussions and 

 compilations of meteorological data relating to India and the neighbouring 

 countries." Vol. vi., Part 5. (Published by order of H K. the Viceroy 

 and Governor-General of India in Council, under the direction of John 

 Eliot, M.A., F.R.S , C.I.E., Calcutta, 1899.) 



NO. I 58 I, VOL. 61] 



masses of air, subject to periodic laws and partaking of the 

 general movement of the air at the earth's surface. In this 

 particular instance, we have the Indo-Gangetic plain stretching 

 from the North I'unjab to East Bengal, some 1350 miles long, 

 and 200 miles in average breadth. The whole of this area is 

 below ICX30 feet in elevation, and probably averages barely 400 

 feet above the sea. From this plain the outer ranges of the 

 Himalayas ri.se with remarkable abruptness over nearly the whole 

 length. On the northern side, by way of contrast, we have the 

 elevated tableland of Thibet, of which a considerable portion 

 exceeds 14,000 feet in elevation, constituting the great pro- 

 tuberance above the general level of the earth's surface, of 

 which the Himalaya and Karakoram mountains are nothing 

 but the northern and southern borders. In this noble theatre 

 and laboratory, the movements of the air peculiar to mountain 

 areas can be studied with effect, and yet, by some strange 

 perversity, the subject has been neglected. The knowledge 

 which we have gained, and which is repeated in text-books, has 

 unfortunately been derived from wind registers which were 

 either not continuous in their action, or from which partial 

 extracts have been made. The records selected for discussion 

 were made at 8 and 10 a.m. and 4 p.m., consequently, the effect 

 of the night winds, accompanying a fall of temperature, did not 

 come within the scope of investigation. Moreover, the stations 

 chosen for the anemometric instruments represented the 

 characteristics of the air movement across the lower mountain 

 ranges and not the local up and down movements in the deep 

 valleys which lie between these ranges. It is therefore not 

 surprising that the results derived from so partial a source need 

 corrections, or that the accounts given by travellers through 

 these districts, limited as they necessarily are to certain seasons 

 of the year, do not adequately represent the whole of the 

 observed phenomena. 



In the opening pages Mr. Eliot briefly reviews the state of 

 our knowledge, and sketches the work of his predecessors in 

 office. The conclusions derived from this haphazard and inter- 

 mittent kind of observation were to the effect that southerly 

 winds prevail throughout the whole year at the Himalayan hill 

 stations, indicating that in the south-west monsoon the lower 

 air current extends to these elevations ; whereas, in the cold 

 weather, the air current giving these winds is the upper move- 

 ment complementary to the north-westerly winds at the level 

 of the plains. Moreover, the records indicated that the air 

 movement is strongest in the Western Himalayas from January 

 to April, and is feeblest during the monsoon period from June 

 to September. To these statements, which have been fre- 

 quently quoted. Sir Richard Strachey added, from his own ex- 

 perience and observation, that the most important feature of the 

 air movementiin the Western Himalayas was the up and down 

 valley winds, blowing up the valleys during the day from 9 a.m. 

 to 9 p.m. and down them during the corresponding hours of 

 the night. 



Mr. Eliot deals with these statements in the first series of 

 tables founded on the records of a large Beckiey anemometer, 

 not particularly described. He gives the number of winds re- 

 corded under each of eight points of the compass for portions 

 of the years 1893-1896, and derives the constants of the well- 

 known Besselian formula representing the diurnal variation of 

 the winds. The result is to show that the mean monthly air 

 movement is in January and February approximately S.E., and 

 for the remainder of the year is N. 46° E. as opposed to S. 61° 

 W. from the partial records already referred to. Other deduc- 

 tions which come out of this preliminary inquiry show that the 

 air movement is least during the rainy season of July and August, 

 greatest from January to May, and that, since the mean move- 

 ment is almost as great in January and February as in 

 the hot weather months, it is not a function of the temperature. 

 Mr. Eliot sums up the general conclusions in the following 

 terms : — "The air moment at Simla varies slightly in strength 

 throughout the year, but has two well-marked maxima and 

 minima, in no way related directly to the seasons or to the air 

 movement over the plains in Northern India. These facts alone 

 constitute a strong proof of the inference that the air move- 

 ment over the Himalayan area is a unique system, independent 

 of the general air movement over the plains in Northern India, 

 and dependent on local conditions and features." 



Neither does the diurnal variation of the wind, whether in 

 velocity or rotation, partake of that simple character which has 

 been ascribed to it, but within a limited space it is not easy to 

 summarise the results of the analysis applied. For Mr. Eliot 



