NOTES 661 



metal castings. With high voltages and heavy outputs steel plates more than 

 I in. thick have been examined successfully. Extraordinary outputs have been 

 obtained by Coolidge on experimental water-cooled models of his tube ; one was 

 run continuously for many hours at o'2 ampere and 70,000 volts, the power output 

 being equivalent to 19 h.p., and he anticipates shortly being able to increase this 

 to about 70 h.p. ! It is the medical application of X-rays which is, however, all 

 important. Their use has extended enormously and stereoscopic methods have 

 attained such delicacy that the location of small foreign bodies near the eye or 

 actually in the eyeball can be carried out to the hundredth of an inch. The rays 

 have proved their value in diagnosing chest complaints, especially incipient 

 tuberculosis ; they are used in dental work and aid plastic surgery in its work of 

 repairing the terrible mutilations caused by shell wounds of the face and head. 

 Turning to the theoretical aspects of the subject Rutherford has recently given 

 evidence for the belief that the wave length of the hardest y rays from RaC is 

 about '01 A.u. while the longest X-ray so far measured by Siegbahn has a wave 

 length of 12 A.u. We are thus acquainted in this region of the spectrum with an 

 unbroken range of frequencies extending over 10 octaves. There is then a gap of 

 5 octaves till we reach 420 A.u., Richardson and Bazzoni's limit in the Lyman 

 region. 



The First Report of the Bristol Grammar School Scientific Society, which has 

 been forwarded to us by the Secretary, shows that the science work in that school 

 is in a very healthy condition and that masters and boys alike are full of enthusiasm. 

 Two evenings each week are given up to practical meetings in the chemical 

 laboratories, each member being expected to draw up for his own use an 

 account of the experiments he performs — a most essential feature but a real 

 criterion of enthusiasm. Lectures are given at frequent intervals by the boys 

 themselves. They are forming an admirable library, including early editions of 

 the works of the eighteenth and nineteenth century chemists and also a herbarium. 



We have received two pamphlets dealing with the Channel Tunnel question. 

 The first, written by Mr. Arthur Fell, M.P., Chairman of the House of Commons 

 Tunnel Committee, deals with the political aspects of the matter. The Cabinet, 

 after consultation with their naval and military advisers, are still opposed to its 

 construction after the war is over. No reasons for this decision have been made 

 public and it has, apparently, caused some feeling of disappointment and dis- 

 quietude in France. The commercial advantages of the scheme are obvious, for 

 it would bring London within six hours of Paris and put it into direct railway 

 communication, without change of gauge, with all parts of Europe except Russia 

 and Scandinavia. The interchange of passenger traffic between England and the 

 Continent is extraordinarily small in comparison with that between any two 

 continental countries. For instance, in 191 1 it was only 1,600,000 as against 

 2,800,000 between France and Germany and 4,350,000 between France, Belgium, 

 and Holland. Moreover, for three English passengers who go to the Continent 

 only one continental passenger comes back ; and if the traffic could be equalised 

 by the construction of the tunnel, it is estimated that England could practically 

 pay the whole cost out of the savings for one year. These geographical aspects 

 of the matter are dealt with in the second pamphlet, which is a reprint of a paper 

 read by Sir Francis Fox, M.Inst.C.E., before the Geographical Society. There 

 are no geological difficulties to be overcome, for the tunnel would be cut through 

 Grey Chalk except near the two coasts, where it would pass through the Gault, and 

 both of these beds are almost if not quite impervious to water. Two tunnels 

 would be bored each about 20 ft. in diameter with cross tunnels every 200 yards ; 



