310 



DISCOVF.HY 



their direction-finding apparatus, Z transmits its 

 bearing to Y, where, with the use of both bearings, the 

 position is plotted and then communicated by wireless 

 to the aircraft. The benefit to aircraft of this develop- 

 ment in wireless is important, but full use has not yet 

 been made of it. It affords a valuable help in aerial 

 navigation — a science in which only a few aviators are 

 sufliciently skilled. To steer an aeroplane or airship 

 in the dark, or over a large expanse of water or desert 

 where no guiding landmarks are available, or in clouds 

 or fog, perhaps, too, in a wind whose speed and 

 direction are only approximately known, is a task not 

 to be undertaken by any ordinary aviator. Yet on 

 long-distance flights such conditions maj' be encoun- 

 tered, and accordingly every possible source of help 

 should be made available to the pilot, and not the least 

 valuable of these sources is the use of wireless direction- 

 finding apparatus. 



Most of the foregoing developments have arisen from 

 the demands of a war in which science has played a 

 great part, and the high state of perfection attained in 

 all types of aircraft wireless work in so short a time has 

 been largely due to the pressure of war conditions. 

 But such developments do not end with the war. 

 Wireless is as essential to civilian aircraft in peace- 

 time as it is to aircraft during war ; it is as necessarj' 

 for the safety of an aircraft and its passengers as it is 

 for the safety of an ocean liner and her 'passengers. 

 Since the Armistice considerable use has already been 

 made of aircraft wireless ; wireless telephony was used 

 with success on the Folkestone-Cologne Aerial Postal 

 Route, and on the London to Paris Air Route (still in 

 use) ; wireless telegraphy and telephony have been 

 largely and successfully used on several long demon- 

 stration flights bj- large aeroplanes, flying boats, and 

 airships. The most important of these was the flight 

 made in July 1919 by the airship " R34," from England 

 to America and back. Her wireless equipment in- 

 cluded a continuous-wave transmitter for long-range 

 work, a low-power spark transmitter for communication 

 with ships, direction-finding apparatus, a wireless 

 telephone, and receiving apparatus with valve amplifier. 

 The wireless results were highly satisfactory and some 

 remarkable ranges were obtained. During the whole 

 flight the airship was in wireless communication with 

 stations on this side, or on the other side, of the 

 Atlantic. Weather reports prepared bj' meteorolo- 

 gists in London were transmitted to her every few 

 hours throughout the flight, and proved of great value. 

 Signals were exchanged with the wireless station at 

 St. John's, Newfoundland, over a distance of more 

 than 1,700 miles. This was the first real test of long- 

 range wireless communication with aircraft, and the 

 results obtained surpassed all expectations. They 

 have demonstrated what can be accomplished, and 



indicate what may be looked for in the future. If 

 civil aviation is to become the success it deserves to 

 be, one can look forward to the days when the world 

 will be traversed by aerial routes o\er which aircraft 

 (both heavier and lighter than air) will fly by day and 

 by night, properly equipped with wireless telegraphy 

 and telephony apparatus by means of which communi- 

 cation-will be maintained with the ground, receiving 

 weather reports, warnings and instructions when 

 necessary, and guided by night and in cloud by a 

 chain of wireless stations acting as " beacons " for 

 direction-finding. 



Note. — There are no textbooks on Wireless in Aircraft, but 

 the reader who is interested in the subject may find some 

 assistance in a series of articles, describing standard types 

 of wireless apparatus used in aircraft during the war, which 

 appeared in the Wireless World (a monthly magazine pub- 

 lished by the Wireless Press, Ltd.), commencing April or 

 May 1919. There are, however, many good te-^tbaoks on 

 Wireless Telegraphy and Telephony. The simplest and most 

 useful of these for the ordinary beginner is probably The Ele- 

 mentary Principles of Wireless Telegraphy, by R. D. Bangay 

 (Wireless Press) ; in this book a section is devoted to oscilla- 

 tion valves and continuous-wave transmission and reception. 

 Other suitable, though more advanced, textbooks are Rupert 

 Stanley's Wireless Telegraphy (Longmans & Co.), Dowsett's 

 Wireless Telegraphy and Telephony (Wireless Press), and 

 Erskine-Murray's Handbook of Wireless Telegraphy (" The 

 Electrician " Series). 



Books of the Month 



The following is our monthly selection of books 

 which we commend to the notice of our readers. 



Fiction 

 The Cross-Pull. By H. G. Ev.\rts. (Hodder & 



Stoughton, 8s. 6d.) 

 Bull-Dog Driimmond. By Cyril McNeile. (Hodder 



& Stoughton, 8s. <bd.) 

 Green Apple Harvest. By Sheil.\ K.vye-Smith. (Cas- 



sell, 8s. bd.) 

 A story of life in Sussex by one who is now ia the first 

 class of novelists. 

 Verena in the Midst. By E. V. Lucas. (Methuen, 



8s. 6d.) 

 They Went. By Norman Douglas. (Chapman & 



Hall, 7s. 6d.) 



Gener.xl 

 On the Art of Reading. By Sir Arthur Quiller- 



CoucH. (Cambridge University Press, 15s.) 

 Collected Poems. By Edward Thomas. Foreword 



by Walter de la Mare. (Selwyn & Blount, 



los. 6d.) 



