2 8o 



NA TURE 



[January 23, 1908 



it would appear that there is considerable scope in South 

 Australia for agricultural investigation, and that a strong 

 scientific staff would prove a really sound investment. 



In a paper on " ghost images " published in the Journal 

 of the Royal Microscopical Society, clxxxi. (December, 1907), 

 Mr. A. A. C. E. Merlin discusses the resolution of the 

 images of a substage stop formed by the secondary mark- 

 ings of the diatom Coscinodisciis asteroniphalus. The 

 diameter of the secondaries was i/83300th of an inch, and 

 the images appeared well defined under a magnifying 

 power of about 3200. In connection with this effect, the 

 author discusses the advantage of high magnification, in- 

 dependently of the question of resolving power, and 

 especially advocates the use of powerful eye-pieces 

 in studying minute structures. While a structure 

 may be equally well defined under a lower magnifica- 

 tion, and may be visible when it is known to exist, the 

 author considers that for the recognition and detection of 

 unknown detail a powerful eye-piece is a necessary adjunct 

 to a picked objective. 



The Transactions of the Theosophical Congress for 1907 

 contain much matter that falls outside the range of 

 " science " as included in the columns of Nature. There 

 are two papers on the dimensions of space which form in 

 some ways an exception to the above statement, and the 

 writer of one of these, who does not publish his full name, 

 gives some diagrams by which it is possible to construct 

 models of projections of the simpler four-dimensional 

 solids. The author, however, considers that the sections 

 of the 600-cell and the 120-cell " become so complicated 

 as not at present to be worth calculating," and on p. 258 

 he shows by his own statements that he is unaware of 

 the work that has been done in " exhausting " the regular 

 figures in space of higher dimensions than four. Indeed, 

 he says : — " It seems to me quite possible that we might 

 find that in a five- or six-dimensional world no regular 

 hypersolids at all were possible." But a little thought 

 can be made to show anyone with a small mathematical 

 knowledge that the triangle-tetrahedron series, the square- 

 cube series, and the octahedron series are capable of 

 extension to space of any dimensions whatever. 



The December (1907) number of the periodical of 

 popular science, Himttiel tiiid Erde, published by the 

 scientific society " Urania," of Berlin, contains an article 

 on the microscopic structure of photographic films by Dr. 

 W. Scheffer. It is illustrated by twenty-two reproductions 

 of photomicrographs, which show how the nuclei of silver 

 salt are affected by various modifications of the times of 

 exposure, the method of development, and the use of 

 intensifiers and of restrainers. 



The December (1907) Bulletin of the Bureau of Standards 

 contains the results of a long investigation on the Clark 

 and Weston standard cells, by Messrs. F. A. Wolff and 

 C. E. Waters. They conclude that the agreement between 

 cells set up with different samples of mercurous sulphate 

 prepared by any of the recognised methods, or by treatment 

 of commercial sulphate with sulphuric acid, is highly satis- 

 factory, and suggest that the standard cell should serve 

 as one of the two fundamental electrical standards. It 

 has been shown that the cells now constructed can be 

 carried long distances without changes of electromotive 

 force of more than a few parts in 100,000 being produced. 

 It will be seen from this statement that the results obtained 

 in America are in agreement with those found at the 

 National Physical Laboratory and communicated to the 

 Royal Society a few weeks ago. 



.'Xn article on some of the present problems of radio- 

 activity, by Dr. G. A. Blanc, appears in the December 

 NO. 1995, VOL. ';y'\ 



(1907) number of Le Radium. The author considers thai 

 Rutherford's disintegration theory is the explanation of 

 radio-activity, and asks whether disintegration is not 

 taking place in all forms of matter? After reviewing the 

 evidence for the a particle being either half an atom of 

 helium with a unit charge or an atom with a double charge, 

 he comes to the conclusion that neither is satisfactorily 

 established. Nor is the genealogical tree of the radio-active 

 elements yet made out. Is it possible, he asks, that lead 

 and silver, which are so intimately associated in nature, 

 belong to this tree, and that one is the parent of the other? 

 The amount of radium in the earth's crust is more than 

 sufficient to maintain the temperature constant, and now 

 he finds there is more thorium present than is necessary to 

 supply the heat required. He is sanguine that some means 

 will eventually be found which will allow us to stimulate 

 radio-active disintegration, and thus obtain a source of 

 energy the utility of which we can scarcely at present 

 conceive. 



The product of the world's gold mines for the year 

 1906 could be all packed in a room 10 feet square and 

 q feet high, says Mr. T. F. Van Wagenen in an article 

 on gold in the current number of the Popular Science 

 Monthly. The value of this 90 cubic feet of gold was 

 nearly eighty-one and a half millions sterling, and its 

 weight nearly 674 tons. Very nearly one-third of this 

 amount was obtained in South Africa, about one-fifth from 

 .Australasia, and nearly a quarter from the L'nited States 

 and Alaska. Eighty-three per cent, of the total output 

 was secured by the .Anglo-Saxon world. .According to 

 calculations and estimates made in 1900 by the director 

 of the United States mint, the gold taken from the mines 

 of the world since the discovery of America has amounted 

 in quantity to about 21,424 tons, and in value to mor- 

 than 2,520,000,000/. Nineteen per cent., or nearly one- 

 fifth of the whole, has been mined in the last ten years, 

 and 30 per cent, in the last twenty years. 



Messrs. Samuel Bagster and Sons, Ltd., have pub- 

 lished a fifth edition of Mr. W. T. Lynn's " Astronomy 

 for the Young." 



.\ second edition of Mr. George J. Gray's " A Biblio- 

 graphy of the Works of Sir Isaac Newton, together with 

 a List of Books illustrating his Works," has been pub- 

 lished by Messrs. Bowes and Bowes, of Cambridge. Th-: 

 work has been revised and enlarged, and many iinportan- 

 additions have been made. 



The first volume of the sixth edition of .\. WuUner'-- 

 " Lehrbuch der Expcrimentalphysik," dealing with genera 

 physics and sound, has just been received from Mr. B. G. 

 Teubner, Leipzig. The volume contains more than a 

 thousand pages, about seven hundred of which are con- 

 cerned with the general properties of matter, while the 

 remainder deal with wave motion and sound. The price 

 of this elaborate treatise on the fundamentals of physics 

 is sixteen marks. 



The ■' International Geography," edited by Dr. H. R. 

 Mill, and written by seventy authors, with special know- 

 ledge of the subjects on which they contribute articles, 

 has been re-publishod by Messrs. Macmillan and Co., 

 Ltd. The work is now issued, not only in one complete 

 volume, but also in parts. The sections dealing re- 

 spectively with the British Isles, Europe, .Asia, .Australasia, 

 North America, South America, and Africa can be 

 obtained separately. The parts each contain a selection of 

 original questions and exercises, and a miscellany of ques- 

 tions set in various public examinations, and they should 

 prove of great service in the higher classes of schools. 



