66 



NATURE 



I^March 1 8, 1909 



of those who are engaged or who seek engagement 

 in this work are hardly to be expected to have any 

 desire to pursue its study into its more difficult 

 theoretical parts ; to such the present volume will 

 prove an adequate guide. To others it will serve as 

 a useful introduction to its more comprehensive prede- 

 cessor. 



A risiimi of the contents is unnecessary; the whole 

 subject is discussed, both in its theoretical and prac- 

 tical aspects, but the treatment throughout is simple, 

 and of such a character that any student with a good 

 grounding in general electrical science and quite 

 moderate mathematical attainments can follow with 

 ease. That the explanations are lucid and the illus- 

 trations plentiful and well chosen goes without saying 

 in reference to any book from Dr. Fleming's pen. 



Of special interest in the present volume are the 

 passages dealing with the production of continuous 

 trains of undamped oscillations by the method of 

 Duddell's musical arc, and in other ways, as this 

 field was barely touched when the previous treatise 

 was published. For the same reason the final chapter 

 on radio-telephony will be read with particular interest. 

 It is to be noted that articulate speech has been 

 successfully transmitted, iii more than one instance, 

 over about 200 miles, and musical sounds about half 

 as far again. As Dr. Fleming says, wireless tele- 

 phony stands now much in the position in which 

 wireless telegraphy stood ten years ago. Time will 

 show whether it can be developed to be of equal utility 

 and service to man. 



M. Turpain's book does for the French student 

 much what Dr. Fleming's does for the English. To 

 attempt an estimation of the relative merits of the 

 two volumes would be an ungrateful task; sufl!ice it 

 to say that the treatment in M. Turpain's book is 

 somewhat less full, but is in all respects clear. In 

 addition, M. Turpain deals with two or three 

 subjects not falling strictly under the classification 

 wireless telegraphy, but closely allied thereto on 

 account of their utilisation of Hertzian waves. These 

 are the application of Hertzian waves to the problems 

 of multiple signalling in ordinary telegraphy .with 

 wires; to the control of moving apparatus, such, 

 for example, as torpedoes, from a distance; and to 

 the study of storms and atmospheric disturbances. 

 There are also two chapters dealing with high- 

 frequency currents and their utilisation for electric 

 lighting. The inclusion of these subjects gives the 

 book a special value, as, to the writer's knowledge, 

 there is no other comprehensive resumi thereof in 

 e.\istence. 



Attention may be directed to the paragraph which 

 closes the first portion of the book which treats of 

 wireless telegraphy alone. The opinion is expressed 

 that wireless telegraphy is not likely to replace any 

 of the existing means of communication, but is 

 destined to find its special sphere in increasing the 

 security — and may one add, the amenity? — of naviga- 

 tion. This view has been frequently put forward in 

 these columns, but as, in the writer's opinion, extra- 

 vagant claims still continue to be advanced for wire- 



NO. 2055, VOL. 80] 



less Transatlantic communication, and large sums of 

 money spent on its development which might be 

 better utilised in less ambitious ways, there can be no 

 harm in its repetition. How wonderfully useful 

 wireless telegraphy has become for the purposes of 

 navigation was strikingly demonstrated for all the 

 world to admire in the case of the wreck of the 

 Republic at the end of January. 



The fourth number of the Jahrhiich dcr drahtlosen 

 Telegraphie iind Telephonie calls for no special 

 comment. Partaking more of the character of a 

 scientific society's journal, reviewing, in the ordinary 

 sense, is more or less impossible. There are a 

 number of original communications on various 

 matters connected with wireless telegraphy, and 

 reports on several practical developments. In addi- 

 tion, the number contains a reprint of the German 

 Act regulating wireless telegraphy according to the 

 international agreement of 1906. 



Maurice Solomon. 



OUR BOOK SHELF. 



Handbuch zur Gcschichte der Natiirwissciischafteit 

 mid der Tcchnik. In chronologischer Darstellung. 

 Zweite, . umgearbeitete und vermehrte Aufiage. 

 Von Prof. Dr. L. Darmstaedter. Unter Mitwirkung 

 von Prof. Dr. R. du Bois-Reymond and Oberst. z 

 D. C. Schaefer. Pp. xfi262. (Berlin: Julius 

 Springer, 1908.) Price 16 marks. 

 This work is a sort of scientific dictionary of dates, in 

 which all the most important discoveries and inven- 

 tions in the world are arranged in chronological order 

 from the year 3500 B.C. down to nearly the begin- 

 ning of the present year of grace. The first important 

 invention noted by the editors is that of the so-called 

 Palmyra books, in which palm paper was first used 

 for writing, the letters being pressed into the leaves 

 by means of a graver or style, and then made visible 

 by being rubbed over with oil and soot. This in- 

 vention is ascribed to the Hindu Sage Panningrishee, 

 of .Arittawarum, on the Ganges. The latest invention 

 chronicled is that of Count Zeppelin's airship which 

 came to grief on August 5 of last year. 



It needs 1070 large octavo pages to describe, in the 

 shortest of paragraphs, all the more significant in- 

 ventions and discoveries which have been made in 

 the space of these 5400 years. Of course, in the 

 earlier years the discoveries and inventions are few 

 and far between, and centuries even elapse before 

 anything can be discovered worth noting, and it is 

 practically only in the beginning of the sixteenth 

 century that each succeeding year is found to produce 

 something sufficiently important to be set down. 

 These great gaps are, of course, due to the imper- 

 fection of the records. No doubt many things were 

 discovered, especially in the East, of which all traces 

 have been lost or at least not hitherto detected, for 

 there is good reason to believe that many inventions 

 of later times usuallv credited to Europeans ought to 

 be ascribed to the people of the East. From the year 

 1500 onwards practically every vear furnishes dis- 

 coveries and inventions which merit being chronicled. 



The plan of the work leaves nothing to be desired 

 as regards simplicity and convenience. The book 

 has a name- and subject-index, but whether the 

 latter is as systematically arranged as is possible is 

 open to doubt. Anvone consulting the work with a 

 view to ascertain the date of a particular discovery 



