272 



DISCOVERY 



illustrated by Sir \\illiam Crookes in the case of these a- 

 particles which produced flashes of light in a dark room 

 when they fell on a screen coated with crystals of zinc 

 sulphide. Other and more recent methods of detecting 

 and counting individual particles electrically and photo- 

 graphically were described by Sir Ernest Rutherford, 

 notably that of Mr. C. T. R. Wilson for observing the 

 track through a gas not only of an a-particle, but also 

 of other types of penetrating radiations. 



Passing on to the various methods of fixing the mass of 

 a single atom and the number of atoms in anv given 

 quantity of matter, Sir Ernest mentioned in particular 

 that devised by Millikan, depending " on comparing the 

 pull of an electric field {i.e. an area charged with electriciiv 

 and therefore magnetic) on a charged droplet of oil or 

 mercury with the weight of the drop." This method with 

 the aid of electrochemical data gives wonderfully accurate 

 results, and Sir Ernest considered it to be one of the 

 most notable experimental achievements "in an era of 

 great advances." 



The President went on to deal with the idea of the 

 atomic nature of electricity and its connection with the 

 problem of the structure of the atom, giving the evidence 

 for the beUef that the atoms of matter are built up of 

 two electrical units, the electron and the hydrogen 

 nucleus — a beUef which may be described superficially 

 with a fair degree of accuracy as showing that matter 

 is really a sort of solidified electricity. 



Next he returned to the question of the detailed 

 structure of the atom, covering far too wide and technical 

 fields of physics and chemistry for so short a summary 

 as this — Geiger's and Marsden's study of the scattering of 

 a-particles, the work of Laue, the Braggs, Moseley, and 

 Chadwick, and the application by Bohr of Planck's 

 Quantum Theory to the problem of the electronic struc- 

 ture of the atom. Very roughly speaking, the modern 

 conception of the atom reached through these researches 

 is of a minute nucleus surrounded by a swirling group of 

 electrons, differing greatly in number and movements 

 according as to whether the type of atom is light or 

 heavy. An analogy, not to be pressed too far, is that of 

 likening the nucleus atom to a " solar system where the 

 sun corresponds to the nucleus and the planets to the 

 electrons." 



A survey of that " comparatively unexplored terri- 

 tory," the nucleus of the atom, followed, including Sir 

 Ernest's and Dr. Chadwick's experiments, Soddy's and 

 Aston's work on isotopes, and researches into the for- 

 mation and disintegration of atomic nuclei (which also 

 give rise to various interesting theories as to the heat of 

 the stars and stellar evolution, and to the conservation 

 and liberation of energy within the universe). 



We must here leave Sir Ernest's survey " of this great 

 period of advance in physical science " — a survey, the 

 value and importance of which, linking up as it does into 

 a homogeneous whole the vastly complicated and widely 

 divergent work of a large number of physicists and 

 chemists, and that puts a completely new interpretation 

 on the structure of matter tliroughout the universe, can 

 be but little realised from this fragmentary outline. 



Science and Transport 



Sir Henry Fowler's address to the Engineering Section 

 followed an interesting discussion on the preceding day 

 between the members of his section and the psychologists 

 on Vocational Tests for Engineering Trades, and in com- 

 menting on the practical application of our vast store of 

 scientific knowledge to engineering he emphasised in his 

 address the " great need for men with the education, the 

 capacity, and the imagination necessary to use this 

 scientific knowledge for the advancement of our profes- 

 sion." Most difficult of all to instil is " that imagination 

 which allows one to see the way in which the knowledge 

 available can be applied in a practical way." 



Transport and its Indebtedness to Science is a big 

 subject to cover. " The transportation which aids civilisa- 

 tion is that which cuts down the wastage of power to a 

 minimum and which reduces the time occupied in carry- 

 ing this out," was Sir Henry's able definition. Taking 

 also the definition in the Encyclopaedia Britannica of 

 Science as " ordered knowledge of natural phenomena and 

 of the relations between them," he went on to show how 

 in this way transportation has been dependent upon it. 



He surveyed the methods of artificial propulsion from 

 the time that Jonathan Halls tried to use a steam engine 

 in a boat on the River Avon in Worcestershire (1736-7) 

 to the present day — the early steam engines and their 

 evolution, the turbine, railway electrification, the internal 

 combustion engine, modern ocean and air transport. 

 On the subject of early railways he recalled a story about 

 Stephenson showing the quickness with which he could 

 apply a known principle to a different object — a faculty 

 which in this case invented the steam whistle. 



" On the Leicester and Swannington Railway, which 

 followed the Liverpool and Manchester, one of the New- 

 castle locomotive drivers — R. Weatherburn — at a level 

 crossing ran into the cart belonging to an old lady, 

 destroying her eggs and butter. L'pon his return to 

 Leicester, and reporting this to Stephenson, he was at 

 once told to go down the town to a trumpet-maker and 

 get him to make a trumpet which could be blown by 

 steam." 



Among other matters Sir Henry considered at some 

 length the evolution in the materials employed for trans- 

 port machinery and engines, alloy steels, light alloys, 

 and the work of himself and his colleagues, which has been 

 exceedingly successful in prolonging the life of the 

 railway locomotive crank axle. 



Education of the People 



After the thoughtless gibberish and " hot-air " of 

 politicians and other second-rate intellects on the ques- 

 tion of education, Professor Nunn's speech on the above 

 subject came like a refreshing breeze. He stated the 

 steadily growing belief that " every member of society 

 has an equal title to the privileges of citizenship ; and, 

 secondly, that the corporate strength of society should 

 be exerted to secure for him actual as well as theoretical 

 possession of his title." 



Education, he considered, should aim at enabling a man 



