September io, 1908] 



NA TURE 



471 



was getting low at the time — between 5 p.m. and 6 p.m. — 

 Captain Daunt believes that the line seen was not of 

 atmospheric origin, for he was unable to see it anywhere 

 else on the disc, and it stopped short a little way on 

 either side of the penumbra. 



The Spectrum of the Nebula HV 15 Cvgni. — The spec- 

 trum of the Milky Way nebula HV 15 Cygni was photo- 

 graphed by Prof. Max Wolf with the Waltz reflector on 

 August 3. An exposure of 3J hours was given, and the 

 resulting spectrum shows the light-source to be gaseous. 



By far the brightest line is that at the violet end of 

 the spectrum, X 373 ; the line at X 434, the band at \ 500, 

 and the lines at KK 369, 397, and 411 are also present, but 

 faint, their intensities being in this order. Possibly there 

 is also a line at X 360, but this is doubtful. Prof. Wolf 

 hopes that by having his mirror re-silvered he will be 

 able to obtain a much stronger spectrum (Astronomischc 

 Nachrichten, No. 4271, p. 379, August 29). 



The Paris Observatory. — M. Baillaud's first report as 

 director of the Paris Observatory gives an account of the 

 work performed during 1907, and follows its predecessors 

 in general form. Among the records of a vast amount of 

 routine work performed there are one or two points of 

 general interest which call for special remark. 



During 1907 the " cercle meridien du jardin " was 

 employed solely for the study of recent improvements to 

 the instrument, and the report gives the results at some 

 length. The automatically registering micrometer has 

 given unhoped-for precision ; the difference of personal 

 equation amongst the observers is practically absent, and 

 shows no variation with the magnitude or with the 

 amount or direction of the motion of the observed object. 

 The mean error of a passage is reduced to +003S. instead 

 of the +005S. obtained by practised observers using the 

 electric method and +0-075. with the eye and ear method. 

 It is hoped to complete the tenth fascicule of the " Atlas 

 photographique de la Lune " during the current year, and 

 it appears necessary that, in order to complete the work 

 satisfactorily, two more fascicules must be issued. 



The new stellar spectroscope, of which M. Baillaud gives 

 an illustrated description, is used, in conjunction with the 

 equatorial coudd, for the determination of radial velocities, 

 and, with its greatest dispersion, gives a spectrum in 

 which, at H7, each millimetre includes four Angstrom 

 units. The time service and the carte du del work have 

 been carried on as usual, and for the latter full statistics 

 are given showing the progress made. 



INSTITUTION OF MINING ENGINEERS. 

 ""PHE nineteenth annual general meeting of the Institu- 

 tion of Mining Engineers, which was held in Edin- 

 burgh on September 2—4, was largely attended, and was 

 altogether a most successful gathering, the papers, dis- 

 cussions, and excursions being all of more than ordinary 

 interest. Dr. R. T. Moore (Glasgow) was elected presi- 

 dent for the ensuing year. The annual report showed 

 that the membership was considerably more than 3000. 

 Tt was announced that owing to the death of the secre- 

 tary, Mr. M. Walton Brown, various changes had been 

 found necessary. The headquarters of the institution would 

 he moved from Newcastle to Westminster, and Prof. 

 L. T. O'Shea (Sheffield University) was appointed 

 honorarv secretary and Mr. P. Strzelecki assistant 

 secretary. 



Of the five papers on the programme, the first read was 

 by Mr. Henry Hall, H.M. Inspector of Mines, on coal- 

 dust and its treatment with calcium chloride. He dealt 

 first with the history of coal-dust in relation to colliery 

 explosions. The first reference to the matter was in a 

 report by John Buddie in 1803, but it was not until 1874 

 that it began seriously to be argued that coal-dust could 

 of itself cause a colliery explosion in the absence of fire- 

 damp. At the present time coal-dust is regarded as the 

 chief agent of destruction. Experiments made by the 

 author showed that the quantity of coal-dust deposited 

 day by day in a mine is much less than is usually thought. 

 When once the roads have been made clean it is easy to 



NO. 2028, VOL. 78] 



keep them so. Watering with the view of laying the dust 

 is impracticable where the rocks are friable shales, as it 

 tends to cause accidents from falls of roof and side. 

 Calcium chloride promises to obviate the difliculty. The 

 application of the solution, or, better still, of the dry 

 powdered salt, is effective for three months. The dis- 

 cussion was well sustained. Mr. H. M. Cadell suggested 

 that a cheaper hygroscopic material, such as common salt, 

 might be tried. Mr. Bennett Brough mentioned that 

 calcium chloride was being successfully used in Wash- 

 ington on macadamised roads to obviate the dust nuisance. 

 Mr. W. C. Blackett stated that calcium chloride had 

 proved efiicacious in a Durham colliery. 



The next paper read, that by Mr. G. B. Walker, 01 

 the practical use of colliery rescue apparatus, embodied 

 a set of rules for the use of such apparatus. He was of 

 opinion that the course that would be adopted in this 

 country was to have central rescue stations maintained by 

 the coal-owners' associations. In the discussion it was 

 suggested that there was a danger of the possibilities of 

 rescue apparatus being exaggerated. Mr. W. E. Garforth, 

 however, strongly supported the views expressed in the 

 paper, and Mr. C. E. Rhodes believed that, apart from 

 the humanitarian aspect of the question, there was great 

 use for the apparatus in saving property in mine fires. 



The paper by Mr. John Gemmell on the Wemyss coal- 

 field contained much interesting historical detail compiled 

 from the journals of the second Earl of Wemyss (1610- 

 1679), who devoted careful thought to the development of 

 the coal seams on his estates. The review of the p'esent 

 condition of the mines contained much information of 

 value. A diamond bore has just been put down on the 

 estate to the enormous depth of 45345 feet. Temperature 

 observations were made, the lowest reading taken being 

 at a depth of 3955 feet, where the temperature was 

 92°-2 F., giving an average thermal gradient from the 

 surface of 1° F. in 87I feet. In the discussion Mr. Brough 

 emphasised the value of the temperature observations in 

 this bore-hole, as it was probably the deepest in Great 

 Britain. The temperature increase was lower than the 

 average of the observations collected by the British 

 .Association Underground Temperature Committee. Mr. 

 J. S. Dixon suggested that this discrepancy could be ex- 

 plained by the cooling action of the flow of water 

 encountered at depths of 1577 feet and 1827 feet. Papers 

 bv Mr. J. G. Thomson on the deep diamond boring at 

 Balfour Mains, Fifeshire, and by Mr. William Caldwell 

 on the working of oil shale at Pumpherston, were taken 

 as read, and the proceedings terminated with the usual 

 votes of thanks. On September 3 the members visited the 

 Wemyss collieries and the Pumpherston oil works and 

 shale mines, and on September 4 there was a steamer 

 excursion to the Kvles of Bute. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Dublin. — In connection with the meeting of the British 

 .Association, the following honorary degrees have been 

 conferred : — D.Sc, Mr. Francis Darwin, F.R.S., Sir 

 David Gill, K.C.B., F.R.S., Dr. William Napier Shaw, 

 F.R.S., Captain Henry George Lyons, F.R.S., Prof. 

 Horace Lamb, F.R.S.,' Prof. Charles Scott Sherrington, 

 F.R.S., Prof. Ernest Rutherford, F.R.S. , Prof. Archibald 

 Byron Macallum, F.R.S., Dr. Albert Kossel, and Dr. 

 .Ambrose Arnold William Hubrecht ; M.D., Sir Thomas 

 Lauder Brunton, Bart., F.R.S. ; LL.D., Sir James 

 .Augustus Henry Murray. 



The new building of the engineering laboratory of the 

 Heriot-Watt College, Edinburgh, will be opened by the 

 Earl of Rosebery on September 16. 



The Board of Education has issued (Cd. 4288) the first 

 part of " Statistics of Public Education in England and 

 Wales, 1906-7-8." The present part is confined to educa- 

 tional statistics ; the second part, which will appear later, 

 will deal wholly with financial statistics. The number of 

 technical institutions in England recognised by the Board 

 during 1906-7 was 31, and the number of teachers 



