148 



SCIENCE-GOSSIP. 



BOOK5TOREaD 





NOTICES BY JOHN T. CARRINGTON. 



Note.— 7« consequence of the great variety in sizes of books 

 no'd) published, the old descriptions, founded on the folding 

 of the paper on which they are printed, will not in future 

 be followed in these pages. In its stead their size, including 

 binding, will be given in inches, the greater being the length 

 and the lesser the breadth, unless otherwise specified. — Ed. 

 Science-Gossip. 



Wireless Telegraphy. By Richard Kerr, F.G.S. 

 126 pp. 6^ in. X 4jin., with 13 figures and 4 por- 

 traits. (London : Seeley and Co., Ltd., 1898.) is. 



Mr. Richard Kerr has succeeded not only in 

 popularly explaining the somewhat mysterious 

 telegraphing without wires, but also in obtaining 

 a preface for his little work from Mr. W. H. Preece, 

 C.B., F.R.S., the Engineer-in-Chief of the British 



has long been strongly suspected that certain 

 oriental races have some knowledge of transmitting 

 signals by means unknown to Europeans, and with- 

 out the aid of telegraph wires or other recognized 

 means of communication, it is only recently that the 

 subject of wireless telegraphy has occupied scientific 

 investigators. So long ago as 1853 that remarkable 

 man James Bowman Lindsay, weaver and self-taught 

 electrician, worked upon the idea, which is now being 

 practically carried out. Indeed, he actually showed, 

 in 1859, the possibility of wireless telegraphy to 

 the members of the British Association at Aberdeen. 

 Still, as Mr. Preece says in the preface to this 

 book, the system was not then practical on a large 

 scale, nor novel, as somewhat similar experiments 

 had been carried out by Morse in 1842. There 

 are now several systems which are successful, all 

 more or less on the same basis. Among these the 

 more important are those of Mr. Preece and Signer 

 Marconi. It was not, however, until Mr. Preece 

 seriously took up the subject some few years ago, 

 and completed experiments, which have been 

 reduced to practice and are now in daily use in 

 the Bristol Channel, that any headway was made 

 in wireless telegraphy. The means by which 



Wireless Telegraphy — Transmitting Apparatus. 



Post Office, and acknowledged authority on tele- 

 graphy. In this preface Mr. Preece states that the 

 author has arranged his subject-matter in readable 

 form, " the illustrations are excellent, and the 

 descriptions of the experiments are accurate." With 

 such an influential introduction we naturally ex- 

 pect much from the hundred and odd pages that 

 follow. Nor are we disappointed, for the lucid 

 style and terse sentences soon give one a good 

 grasp of the whole subject of wireless telegraphy. 

 Mr. Kerr has divided his book into an intro- 

 duction, eight chapters, and appendix. The titles 

 will give a good idea of the plan and contents 

 of the book, they are (i) " Supposed Oriental 

 Powers of Signalling through Space without 

 Wires"; (2) "Is there Anything Solid?" (3) 

 "Vibrations in Air and in Ether"; (4) "James 

 Bowman Lindsay " ; (5) " Induction Experiments 

 by W. H. Preece, C.B., F.R.S." ; (6) " Hertzian 

 Waves — Experiments by Signer Marconi " ; (7) 

 " Hertzian Waves — Experiments by Dr. Lodge, 

 F.R.S., and others" ; and (8) "The Uses of Wireless 

 Telegraphy." The appendix contains detailed 

 descriptions of a technical character of various 

 terms and instruments mentioned in the preceding 

 chapters. Although, as the author points out, it 



wireless signalling is attained may shortly be 

 stated to be the adaptation of the wavelets 

 of electricity created by sudden agitation, 

 in much the same way as wavelets result when 

 one throws a stone into still water. These spread 

 in all directions, and it is only necessary to arrest 

 them at any point to get an exact record of their 

 formation by the person desiring to communicate 

 with us. These electrical wavelets or ripples move 

 with almost inconceivable speed, passing through 

 anything or everything at a rate equal to one 

 hundred times round the earth in a dozen seconds. 

 To understand this the better we must remember 

 that as water has its ripples, so has air, which 

 convey to us sound. The medium known as ether 

 appears to be that which supports the electric 

 waves used in these experiments. This was first 

 indicated by Clerk Maxwell, and later experi- 

 mentally detected by that brilliant physicist, 

 Dr. Hertz, who died in 1894, ^.H too soon, at the 

 early age of thirty-seven. Hence it is that these 

 vibrations or wavelets have come to be known as 

 the Hertzian waves. As these vibration ripples go 

 everywhere and may be stopped and studied by 

 anyone, it was necessary to invent an instrument 

 which would maintain the secrets of the Telegraph 



