24 



NA TURE 



[July i, 1922 



was germinating. The massive cotyledonary tube 

 emerges from the nut, carrying the plumule and 

 radicle out of the seed, and later the plumule pushes 

 through the tube and grows up into the air. Speci- 

 mens of the tubers of Ecanda rubber (Raphionacme 

 utilis, Brown and Stapf) from Angola, which some- 

 times weigh as much as 15 lbs., and contain valuable 

 rubber, were also shown. 



Mr. W. Barlow exhibited some models of organic 

 substances which are based on the law of valency- 

 volumes and are in harmony with the Bragg 

 structure found in the diamond. The valency- 

 volume unit-cell appropriate for the carbon com- 

 pounds is a rhombic-dodecahedron. The funda- 

 mental valency of carbon is expressed by a close 

 tetrahedral group formed of four of the cells — that of 

 nitrogen by three cells triangularly arranged, that of 

 oxygen by two cells in face-contact, and that of 

 hydrogen by a single cell. By fitting together 

 appropriate numbers of these cells representing the 

 composition and constitution of various compounds, 

 structures can be made representing molecules which 

 present internal symmetry closely corresponding 

 with that of the crystal forms of these organic sub- 

 stances. 



The Research Department, Woolwich, had an 

 exhibit showing the time reaction in the colour change 

 of Congo red in organic solvents. The change from 

 red to blue which occurs during titration is associated 

 with its flocculation from the colloidal condition and 

 forms a time reaction related to the concentration of 

 H ions and other properties of the solvent. There 

 were also exhibits from the Air Ministry (Instru- 



ment Section), among which was a radiator tempera- 

 ture outfit designed to determine the temperature 

 distribution at different points on an aero-engine 

 radiator and its connecting pipes. A six-junction 

 thermocouple is used, and each set of junctions 

 measures the temperature relative to that of the 

 atmosphere. Another exhibit was a Filon aneroid 

 dial for indicating to the pilot the height of an 

 aeroplane above the ground. The scale is coiled into 

 a spiral groove so that it can be adjusted to meet daily 

 changes in temperature and barometric pressure. A 

 metallic oxygen container was also shown in which a 

 small quantity of silica-gel has been used successfully 

 for cleaning up residual gases. 



Mr. A. A. Campbell Swinton demonstrated the 

 recording of wireless telegraphic messages. A short 

 aerial on the roof of the building was connected 

 through a tuner to a thermionic three valve amplifier, 

 which in turn was connected to a 1 to 3 valve note 

 magnifier. A moving coil siphon recorder was used, 

 connected to the note-magnifier, either through a 

 Brown relay, or through a very low frequency 

 thermionic amplifier tuned to respond to the frequency 

 of Morse signals. For the reception of continuous 

 wave signals a separate thermionic heterodyne 

 oscillator is employed which renders the high fre- 

 i quency signals audible by means of musical " beats." 

 Dr. H. E. Hurst and Mr. D. A. Watt exhibited an 

 interesting model, on a scale of 1 : 50, of the sluice of 

 Aswan dam which is used for calibration purposes. 

 The relation between Q, the discharge of the actual 

 sluice, and q the discharge of the model is given very 

 closely by Qjq =11 .5/2, where n is the scale ratio. 



Psychical 



THE Journal of the Washington Academy of 

 Sciences of March 19 contains a communica- 

 tion from Mr. L. T. Troland of Harvard University 

 entitled ' ' Psychophysics as the Key to the Mysteries 

 of Physics and Metaphysics." The article is in- 

 teresting as a revival of the once famous theory 

 of mind-stuff put forward by W. K. Clifford in his 

 lecture on " The Nature of Things in Themselves." 

 Mr. Troland connects it with several recent philo- 

 sophical theories of psychical monism and brings it 

 forward with particular reference to the consequences 

 of adopting the principle of relativity and the quantum 

 theory in physics, both of which, he contends, demand 

 the recognition of the ultimate psychical nature of 

 physical reality. 



The essence of the mind-stuff theory is that 

 it supposes mind to be constituted and articulated, 

 not merely on the analogy of physical reality but 

 on one and the same principle, so that a parallelism 

 runs throughout the universe between mind and 

 matter. Every electron or proton has not only a 

 psychical aspect but in its ultimate nature is a con- 

 stituent of mind, a bit of mind-stuff. Just as the 

 unit of physics, the electric charge, enters into com- 

 bination in atoms, molecules, and their more or less 

 stable compounds, acquiring thereby the various 



Monism. 



physical and chemical properties of things, so the 

 mind-stuff combines to acquire the various sensational, 

 emotional, and intellectual properties of personalities. 



Mr. Troland's argument is interesting but scarcely 

 convincing. He thinks by the theory to get over 

 Berkeley's difficulty that no qualities of things, 

 primary or secondary, are independent of the observ- 

 ing individual. The new realists, though they have 

 recently attached Berkeley, have not, he thinks, 

 succeeded as yet in developing an explanation of the 

 universe which is either simple or plausible. 



The difficulty of Mr. Troland's theory, however, if 

 offered as a support of Einstein, would seem to be that 

 it misses the essential difference between the activity 

 of the observer co-ordinating events in space-time 

 systems and the intersecting world-lines which present 

 the events co-ordinated. The theory of knowledge we 

 are waiting for in science as well as in philosophy is 

 one which will give full meaning to the subjective and 

 1 ibjec ti\ c factors without sacrificing either to the other. 

 Psychical monism seems to be no more successful 

 than physical monism as a key to the mysteries of 

 physics and metaphysics, but we commend Mr. 

 Troland's argument, which includes in its scope recent 

 physiological research as well as the new physical 

 theories. 



Technical 



THE annual conference of the Association of 

 Teachers in Technical Institutions was held on 

 June 5-7 in London, and in the course of his pre- 

 sidential address. Mr. J. Paley Yorke claimed very 

 strongly that technical education is definitely educa- 

 tion and is as essential as any other branch of 

 educational activity. He said that technical educa- 

 tion is essentially scientific education, and urged 



NO. 2748, VOL. I 10] 



Education. 



that the advance of scientific knowledge and the 

 development of the applications of science to industry 

 and manufacture have been so tremendous that the 

 time has arrived when a special committee of inquiry- 

 should be appointed to investigate the whole field 

 of technical education in relation to industry and 

 to education generally. It is now forty years since 

 there has been any national inquiry on technical 



