N< >\ EMBER 25, 1922] 



NA TURE 



Calendar of Industrial Pioneers. 



November 26, 1836. John Loudon McAdam died. — 

 The great improver of road-making, McAdam began 

 his experiments in Ayrshire, continued them at 

 Falmouth, where he was a contractor for the Navy, 

 and in 1815 was made surveyor general of the Bristol 

 roads, where he introduced the method of forming 

 a bed of stones broken into angular pieces. His 

 process was gradually adopted with great advantage 

 to commerce in all parts of the world. 



November 27, 181 1. Andrew Meikle died. — A mill- 

 wright of Houston Mill, Dunbar, Meikle was the 

 inventor of the modern type of threshing-machine. 

 His machine is said to have saved this country 

 2,000,000/. per annum. In 1784 he conceived the 

 idea of drums armed with beaters, and the first machine 

 was made in 1786. He continued to improve it, 

 but reaped little pecuniary benefit from his invention. 

 In 1809 a subscription for him realised 1500/. 



November 28, 1894. Sir Henry Hussey Vivian, 

 first Baron Swansea, died. — The son of a merchant con- 

 nected with the copper-smelting industry, Vivian, after 

 leaving the University of Cambridge, directed works 

 at Swansea, patented improvements in metallurgy, 

 and introduced the manufacture of spelter and the 

 production of nickel and cobalt. Through his efforts 

 Swansea became " the metallurgical centre of the 

 world." Vivian was remarkable for his energy and 

 ability ; he took part in local and national affairs, 

 and after sitting in Parliament for many years was, 

 in 1893, raised to the peerage. 



November 29, 1766. John Wyatt died. — With 

 Lewis Paul, Wyatt is credited with the important 

 invention of spinning bv machinery. Originally a 

 carpenter in his native village near Lichfield, he 

 afterwards entered the employ of Matthew Boulton. 

 The compound weighing-machine now in general 

 use and the roller bearing were invented by him. 



November 30, 1866. John Mercer died. — Born in 

 Lancashire in 1791, Mercer began work at nine as 

 a bobbin-winder and became a hand-loom weaver. 

 He studied mathematics and chemistry, became known 

 for his experiments in dyeing, and, from 1825 to 

 1848, was partner witii Fort Brothers. He contributed 

 to the chemistry of dveing, propounded a rational 

 theory of catalytic action, and in 1850, after a long 

 series of experiments, discovered the process of 

 " mercerising." 



November 30, 1906. Sir Edward James Reed died. — 

 One of the foremost naval architects of his time, 

 Reed was trained as a shipwright in the Royal 

 Dockyards. In 1S60 he became the first secretary 

 of the Institution of Naval Architects, and in 1863, 

 at the age of thirty-three, was made chief constructor 

 of the Navy, a post he held till 1870. He introduced 

 the belt and battery system and designed H.M.S. 

 Devastation, the first mastless sea-going turret iron- 

 clad. He afterwards designed many notable vessels 

 for foreign navies, and as a public man was a strenuous 

 advocate of scientific and technical education. 



December 1, 1850. Aaron Manby died. — The 

 builder of the first iron steam vessel to make a sea 

 voyage, Manby founded the Horseley Iron Works 

 at Tipton, Staffordshire, where, in 1821, he built the 

 Aaron Manby of iron. This vessel was sent to London 

 in pieces, put together in the Surrey Canal Dock, 

 and in June 1822 crossed the Channel, taking a 

 cargo of iron castings to Paris. Manby in 1819 

 established important engineering works at Charenton, 

 supplied some of the earliest engines for the French 

 Navy, and took a prominent part in the lighting 

 His by gas. E. C. S. 



NO. 2769, VOL. I IO] 



Societies and Academies. 



London. 



Royal Society, November 16. — Sir Charles Sherring- 

 ton, president, in the chair. — A. S. Eddington : The 

 propagation of gravitational waves. The potentials 

 given in Einstein's theory represent not only the 

 absolute gravitational disturbance of the field, but 

 also the metric of the co-ordinate system which is to 

 a great extent arbitrary ; consequently the speed 

 of propagation of the potentials is not necessarily 

 the speed of the absolute disturbance. Einstein 

 showed that, when the co-ordinate frame is chosen 

 subject to a certain restriction, the potentials are 

 propagated with the speed of light. Considering the 

 propagation of plane waves on unrestricted co- 

 ordinates, it is found that " transverse-transverse " 

 waves continue to have the speed of light, whereas 

 the other two types of waves have no fixed speed 

 when Einstein's restriction is removed. The latter 

 types do not correspond to any- absolute disturbance 

 of the field. Of the three conceivable types of 

 transverse-transverse waves, one is inconsistent with 

 the equations of entirely empty space, G M i.= o ; but 

 this type nevertheless commonly occurs in Nature, 

 namely, as a propagation of gravitational disturbance 

 by light-waves. Divergent waves are also considered. 

 Although the equations correspond to those of sound- 

 propagation, no uniform spherical waves of gravita- 

 tion can occur ; they must always be complicated 

 bv doublet-sources for some of the components. 

 The waves emanating from a spinning rod are worked 

 out in detail, and it is found that (in agreement with 

 Einstein) the rod must slowly lose energy by these 

 waves ; for a typical example the period of deca3 r 

 of the rotation is found to be of the order io 35 years. 

 — J. H. Jeans : The theory of the scattering of o- 

 . and /3-rays. A theory of scattering is developed in 

 which both the feeble encounters of the theory of 

 multiple scattering and also the violent encounters 

 of the theory of single scattering are taken into 

 account. The presence of single scattering produces 

 very nearly the same effect as can be produced by 

 a suitable adjustment of the constants in the law 

 of multiple scattering, and this renders the separate 

 experimental study of single scattering very difficult. 

 — A. P. Chattock and L. F. Bates : On the Richardson 

 gyro-magnetic effect. Richardson has shown that 

 the angular momentum arising in a ferro-magnetic 

 substance from unit change in its magnetic moment 

 should have the value of 1-13x10-' if gyrating 

 electrons are responsible for its magnetism. Measure- 

 ments of this quantity by the ballistic method for 

 three specimens of iron and one of nickel are given. 

 The results, divided by i-i3Xio" 7 , agree to within 

 1 \ per cent, with one" another, and their mean is 

 o-6 per cent, greater than 0-500. Close proportion- 

 ality also exists between the change of magnetic 

 moment and the angular momentum resulting. The 

 specimen used consisted of an upright wire suspended 

 by a quartz fibre. By the introduction of a hinged 

 joint between wire and fibre the adjustment of the 

 magnetic axis of the wire to the vertical is much 

 facilitated, and measurements were made on reversal 

 of magnetism instead of on merely reducing it to 

 zero. The more perfect symmetry resulting from 

 this procedure may be the cause of the more consistent 

 results obtained. The effect on the results of the 

 eddy currents in the specimen was not more than 

 a small fraction of 1 per cent, for the specimens used. 

 Al high dampings the ordinary damping correction 

 gives values that are too large.— P. M. S. Blackett : 

 On the analysis of a-ray photographs. A large 



