496 



MA TURE 



[March 26, 1908 



Among other useful articles wo may mention Mr. W. A. 

 Bentley's interesting studies of frost nnd ice crystals, and 

 a mathematical investigation by Prof. F. H. Uigelow on 

 vortices in the atmosphere. 



TiD.Ai. bores in China and Japan form the subject of two 

 recent p.ipers differing widely in character. In the Popular 

 Science Monthly for March Dr. Charles Keyser Edmunds 

 ijives an illustrated account of his visit to the Hangchow 

 bore, while a bore in Odawara which sometimes does much 

 destruction is treated, from the hydrodynamical point of 

 view bv Prof. H. Nagaoka in a short note in the Pro- 

 ceedings of the Tokyo Mathematico-Physical Society for 

 November last. 



The Bulletin of the American Mathematical Society for 

 March contains an account of a joint meeting held at 

 Chicago in December last between mathematicians and 

 engineers for the discussion of the teaching of mathematics 

 to engineering students. The discussion in question refers 

 mainly to the mathematical requirements of the average 

 engineer who is occupied exclusively in practical applica- 

 tions of known methods. Little or nothing is said by the 

 speakers about the growing need of original workers, who, 

 by bringing the highest mathematical knowledge to bear 

 on engineering problems, are able to devise new methods, 

 and to guide the ordinary practical e.xperimenter. 



A SUGGESTION for a new economic arithmetic is the 

 subject of a short paper in the Economic Journal for March 

 by Prof. T. N. Carver. The author's ideas are simple and 

 practical, and at the same time scientific. He considers 

 that the teaching of arithmetic can be illustrated with 

 advantage by simple problems based on tables, of which 

 he gives as an example one showing the quantity of corn 

 grown with varying quantities of labour on a given quantity 

 of land. The problems that can be worked out as exercises 

 with such a table include the following ; — Given the cost 

 of labour and the value of the corn, how many days' 

 labour can be most profitably devoted to the cultivation of 

 the fields? Or, again, given the number of available 

 days' labour, how many acres can be most profitably 

 cultivated? It is pointed out that complicated mathematical 

 methods or the plotting of curves are unnecessary for the 

 solution of such simple problems, and the author quotes 

 the existing methods of dealing with tariff reform contro- 

 versy as an instance of the want of such simple training. 

 In support of the author's view, it must be admitted that 

 there is a great deal commonly taught under "arithmetic" 

 which might well be superseded by such studies as he 

 suggests. But where are the statistics necessary for such 

 a course to be obtained? 



The National Geographic Magazine (xix., i) contains 

 an illustrated account of Dr. Alexander Graham Bell's 

 experiments with his Cygnet man-lifting kite. This kite 

 was sent up in December, 1907, both with and without a 

 man, Lieut. Selfridge having ascended 168 feet with it, 

 and having remained in the air for more than seven 

 minutes. The kite is described as " tetrahedral " in shape 

 — perhaps it would be better to describe it as a triangular 

 •prism with oblique ends. It measures 13 metres laterally 

 at the top and 10 metres at the bottom, 3 metres longi- 

 tudinally at the bottom, and 3 metres in oblique height. 

 It lonsists of 3393 winged cells having a surface of 

 iS,V(< square metres. It weighs 85 kilograms, and is 

 provided with floats, weighing 9-4 kilograms, which enable 

 it to rest on the surface of a sheet of water. In the 

 experiments performed at Baldeck, Nova Scotia, the kite 

 flew with remarkable steadiness, and Dr. Bell considers 

 NO. 2004, VOL. 7j'\ 



this fact a justification for extending the experiments to 

 motor-driven machines constructed on a similar principle. 



A\ interesting lecture was given by Sir William Preere 

 at the Institution of Electrical Engineers on March 12 on 

 his recent visit to America, and the various improvements 

 in constructional and engineering work since his previous 

 visits were dealt with. The sky-scraper buildings appear 

 to afford a considerable day load in that they employ 

 numerous lifts which are constantly in use, but the public 

 supply does not benefit from these very much, as in the 

 larger buildings the tendency is to erect private plants. 

 On the telephone question, America seems to have gone 

 ahead of us on this side. In most of the hotels telephones 

 are installed in every bedroom, so that business may be 

 transacted with any part of the country. This applies 

 also to the restaurants, where telephones may be plugged 

 on to your table if desired. The Telephone Tariff question 

 has also been thoroughly considered in America, and the 

 message rate has been adopted in preference to the simple 

 annual rental. 



In the Proceedings of the .American Academy of Arts 

 and Sciences (vol. xliii., No. 12) Messrs. Gregory P. Baxter 

 and John H. Wilson describe a number of re-determina- 

 tions of the atomic weight of lead, the true value of 

 which is at present uncertain owing to the wide dis- 

 crepancies in the results of previous workers. The method 

 of analysis adopted consisted in determining the proportion 

 of chlorine in lead chloride by precipitation with silver 

 nitrate ; this method seemed the best to use in view of the 

 fact that the halogen can be determined w^ith great 

 accuracy, and the elimination of moisture from lead 

 chloride is easily effected by fusion of the salt in a current 

 of hydrogen chloride. Silver chloride, moreover, when 

 precipitated from a dilute solution of lead chloride, does 

 not contain an amount of occluded lead salt large enough 

 to be detected. Special care was taken, of course, in the 

 purification of the materials employed. The results 

 obtained, were very concordant, varying in one series, in 

 which the ratio PbCl, : 2.\g was determined, from 207-173 

 to 207-202, with an average of 207-188; in another series, 

 based on the ratio PbCU : 2AgCI, the average 207-191 was 

 obtained, with a range of variation from 207-181 to 207-204. 

 The mean result, Pb = 207-i9 (0 = i6, Ag=io7-93), is nearly 

 three-tenths of a unit higher than the value for the atomic 

 weight of lead now in use. 



A SECOND edition of Mr. J. \\'. Ilayward's " First Stage 

 Steam " has been published by .Mr. W. B. Clive. 



The spring list of the Oxford University Press includes 

 " I-'loral Mechanism " (part i., types i to 12), bv Dr. 

 .\. H. Church, and " Lectures on Evolution." by Prof. 

 E. B. Poulton, F.R.S. 



Messrs. .'\. Gali.enk.^.mp and Co., Ltd., have issued a 

 catalogue of the Meker hot-flame burners, Dennstedt's 

 combustion furnaces, accessories for use with the furnaces, 

 and cylinders of compressed air, which Ihev are now pre- 

 pared to supply. 



.\ NINTH edition of Mr. W. T. Lynn's " Remarkable 

 Eclipses " has been issued by Messrs. S. Bagster and 

 Sons, Ltd. The booklet has been brought up to date, and 

 provides a sketch of interesting facts connected with solar 

 and lunar eclipses. 



Messrs. A. and C. Black will publish shortly a book on 

 " Kafir Socialism," by Mr. Dudley Kidd ; a book on botany 

 for young children, by Mr. O. V. Darbishire, of Man- 

 chester University ; and a re-issue, at a popular price, of 



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