4 50 



NATURE 



[August 2, 19 17 



The description in ha Nature for June 16 of the 

 equipment of one of the large German bombing- 

 aeroplanes made by the Gotha Wagonenfabrik 

 and captured by the French in February shows 

 that at that date these planes were only intended 

 to drop bombs when moving with or against the 

 wind, and not athwart it. The bomber sits in 

 front of the pilot and is provided with a tele- 

 scope about a metre long with a small magnifica- 

 tion and a wide field of view. It is fixed in 

 gimbals near his feet, and can be kept vertical 

 by him with the help of a circular level, an image 

 of the air-bubble of which is projected into the 

 eyepiece. Below the objective an achromatic 

 prism is placed with its refracting edge perpen- 

 dicular to the axis of the telescope. By means 

 of a graduated disc close to the eyepiece the 

 prism can be rotated about a line perpen- 

 dicular to the axis of the telescope, so that the 

 line of sight of the telescope continues beneath 

 the prism at any required angle up to about 30° 

 with the axis of the telescope. 



A stofHwatch with its dial close to the eyepiece 

 enables the preliminary speed observations to be 

 readily made. The prism can then be clamped at 

 the proper angle for the conditions found, and on 

 looking down the telescope the bomber sees at 

 €ach instant in the middle of the image 

 of the air bubble and in the centre of 

 his field of view the spot on which a 

 bomb released at that instant would drop. If 

 the aeroplane is moving directly tow'ards a point 

 in the air from which a given object can be 

 bombed, the image of that object will move to- 

 wards the centre of the field along a fore-and-aft 

 line in the field. If the aeroplane is not moving 

 ■directly towards the object, the observer has to 

 rotate the telescope about a vertical axis to bring 

 the object into the fore-and-aft line. The rotation 

 of the instrument is recorded on a dial before the 

 pilot, who alters the direction of flight until the 

 •observer can bring the telescope back to its normal 

 position and the dial in front of the pilot shows 

 no error of direction. 



The instrument is made by the firm of Goerz, 

 and there is no difficulty in modifying it so that 

 the restriction of its use to flights with or against 

 the wind no longer holds. Whether this 

 has been found advisable may be doubted, in view 

 of the uncertainty which always exists as to the 

 character of the air movements between the aero- 

 plane and the ground. C. H. Lees. 



NOTES. 



With reference to the paragraph which appeared in 

 a recent issue of Nature regarding the Society de 

 •Chimie Industrielle, further particulars as to the scope 

 of the new society appeared in L'Echo du Coinmerce 

 for July 20. The object of the societ}' will be to pro- 

 mote the science of chemistry as applied to industry. 

 Local provincial branches will be formed which, while 

 being self-governing, will keep in touch with the parent 

 society at Paris. The society will institute research 

 work with the view of assisting manufacturers and 

 agriculturists. An institute and library are in contem- 

 plation which will contain a complete collection of 



NO. 2492, VOL. 99] 



French and foreign periodicals devoted to industrial 

 chemistry, and the society hopes to arrange for meet- 

 ings, exhibitions, etc., to stimulate activity. A review 

 — the first number of which is expected <o be pub- 

 lished shortly — will keep manufacturers posted in the 

 latest developments at home and abroad, describe in- 

 ventions and processes, and, generally, fill a want 

 that has been long felt in France. The first council 

 of the society contains many names prominent in the 

 scientific and industrial world. 



For some days the firing in Flanders has been un- 

 usually heavy, culminating in the Allied attack on 

 Tuesday, July 31. On Saturday last, July 28, ac- 

 cording to a message from Amsterdam, the 

 thunder of the guns reached a greater pitch of 

 intensity than ever experienced previously. A similar 

 remark is made by *he Dover correspondent of 

 the Times (July 30). The firing heard in that town 

 was almost continuous throughout the night of July 

 28-29, ^"d was particularly heavy about midnight and 

 just before daybreak. A correspondent of the Daily 

 Telegraph states that, on the afternoon of July 25, 

 " while yet the hum of the London traffic was 

 dominant, the sullen boom of the guns in Flanders was 

 heard in many districts in South London. As the 

 evening advanced the sound became a low growl, un- 

 mistakable, and practically continuous." The sound 

 of the heavy firing on Tuesday was also heard dis- 

 tinctly in London. 



The current Quarterly Review contains an article by 

 Dr. C. Davison on his investigation of the sound-waves 

 of the East London explosion of January 19 last. 

 As stated in Nature for February i (p, 438), the 

 sound-area consists of two detached portions,. The 

 inner sound-area is distorted in two main directions. 

 Towards the east-south-east it reaches Canterbury, 

 48 miles, and to the north-west Wellingborough, 

 665 miles ; but to the north-east and south the 

 boundary is only 19 or 20 miles from the source. 

 The outer sound-area reaches from near Notting- 

 ham, across the south of Lincolnshire and Norfolk, 

 to, and no doubt beyond, the east coast of the latter 

 county. The most distant place at which the sound 

 was certainly heard is Stow, near Lincoln, 128 miles. 

 The width of the silent zone varies from 28 miles at 

 the western and higher end to 48 miles at the eastern 

 end. Speaking- generally, the inner sound-area was 

 one of single reports and the outer area one of mul- 

 tiple reports — two, three, and sometimes four reports 

 being heard in quick succession. The existence of 

 inaudible air-waves was manifested by the shaking 

 of windows and the disturbance of pheasants, and 

 the arrival of these waves was not, as a rule, coin- 

 cident with that of the sound-waves. Within 15 or 

 20 miles of the source the air-waves passed after 

 the sound was heard, at greater distances usually 

 before. The air-waves were not, however, confined 

 to the sound-areas, for their effects were noticed at 

 sixteen places vi^ithin the. silent zone, nine of them 

 being in the narrow western portion. The sound 

 was heard at Ipswich, which lies a few miles from 

 the northern boundary of the silent zone, and possibly 

 also at Uppingham and Lilford, near the western end. 

 It is inferred that both the inaudible air-waves and 

 the sound-waves crossed the silent zone at moderate 

 heights above the ground, but that the air-waves fol- 

 lowed a lower path than the sound-waves. 



Early in July Mr. Erik Andersson, of Uppsala, 

 again led to Spitsbergen a geological expedition, which 

 included Messrs. Adam Reuterskiold, Sven Yd^n, and 

 Karl Samuelsson. The main object was to continue 

 the investigation of the Trias and to collect saurians 

 and fishes. The occurrence of phosphorite at Cape 



