1 64 



NATURE 



[December 19, 1907 



whicli is now being carried out at tlio polyteL-linic, at a 

 cost of i2,ooq;., toward which the late chairman of the 

 jiovorning body, Mr. Edric Bayley, has generously con- 

 tributed the sum of 5000/., the remainder being made up 

 by a grant from the London County Council. Mr. C. T. 

 Minis, the principal, in his report, stated that there were 

 nearly 3000 individual students in attendance during the 

 past session, of whom 330 were day students. 



We have received the calendar of the Camborne Mining 

 School, Camborne, for 1907-S. This school, now in the 

 twentieth year of its existence, has rapidly expanded, and 

 has proved very successful in giving facilities to students 

 for acquiring a thorough knowledge of metalliferous 

 mining. The success has been largely due to the organisa- 

 tion of a systematic course of practical mining, the South 

 Condurrow, now known as the King Edward mine, having 

 been purchased for the purpose in 1897. Students there 

 obtain an acquaintance with practical mining, ore dress- 

 ing, and engine testing, as well as practice in mine survey- 

 ing under the supervision of practical men under the direct 



its present stage. The work at South Kensington, as is 

 well known, is largely due to his instigation and interest, 

 and the new Technological Institute which will begin in 

 the coming year will be a natural outcome of that work. 

 By means of it we hope to be brought more into line with 

 o'.hcr nations." 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, November 7.— "The Diurnal Variation of 

 Terrestrial Magnetism." By Prof. .-Xrlhur Schuster, 

 F.R.S. 



In a previous communication (Phil. Trans., vol. clxx.x., 

 p. 467, 1889) the author proved that the diurnal variation 

 of terrestrial magnetism had its origin outside the earth's 

 surface, and drew the natural conclusion that it was caused 

 by electric currents circulating in the upper regions of the 

 atmosphere. If we endeavour to carry the investigation 

 a step further, and consider the probable origin of these 



nderground in King Edward Mil 



authority of the school. Moreover, in consequence of the 

 situation of the school in the centre of the chief mining 

 district of Cornwall, students have the privilege of visiting 

 the mines. The calendar is illustrated by a number of 

 admirable photographic views, many of which have been 

 taken by Mr. J. C. Burrow, the leading exponent of 

 underground photography. The photograph here repro- 

 duced represents the so-called " cathedral " at the 460-feet 

 level of King Edward mine. 



Mr. Haldane, M.P., unveiled a statue of the King at 

 University College -School, Frognal, Hampstead, on 

 Saturday, December 14. The statue has been erected in 

 a niche above the main entrance, and is presented to the 

 school by the architect, Mr. Arnold Mitchell, in com- 

 memoration of the opening of the school by the King on 

 July 25. In a subsequent address Mr. Haldane said : — 

 " There is no subject of greater general importance than 

 education, and if Prince Albert had lived there is no doubt 

 that education would have been ten vears in advance of 



currents, we have at present no alternative to the theory, 

 first proposed by Balfour Stewart, that the necessary electro- 

 motive forces are supplied by the permanent forces of 

 terrestrial magnetism acting on the bodily motion of masses 

 of conducting air which cut through its lines of force. 

 In the language of modern electrodynamics, the periodic 

 magnetic disturbance is due to Foucault currents induced 

 in an oscillating atmosphere by the vertical magnetic force. 

 The problem to be solved in the first instance is the specifi- 

 cation of the internal motion of a conducting shell of air, 

 which shall, under the action of given magnetic forces, 

 determine the electric currents producing known electro- 

 magnetic effects. Treating the diurnal and semi-diurnal 

 variations separately, the calculation leads to the interesting 

 results that each of them is caused by an oscillation of the 

 atmosphere w^liich is of the same nature as that which 

 causes the diurnal changes of barometric pressure. 



The mathematical analysis is simple so long as we take 

 the electric conductivity of the air to be uniform and con- 

 stant ; but the great ionisation which the theory demands 



NO. 1990, VOL. ■/■;] 



