A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

 Of Nature trusts the mind which builds for aye."— Wordsworth. 



THURSD.W, NOVEMBER 3, 1904. 



APPLIED ELECTRICITY. 

 (i) Wireless Telegraphy. By C. H. Sewall. Pp. 229. 

 (London : Crosby Lockwood and Son, 1903.) Price 

 IDS. 6d. net. 



(2) Electricity in Agriciillurc and Horticulture. By 

 Prof. S. Lemstrom. Pp. iv + 72. (London: The 

 Electrician Printing and Publishing Co., Ltd., 1904.) 



(3) Modern Electric Practice. Vol. iv. Edited by 

 Magnus Maclean. Pp. viii + 304. (London: The 

 Gresham Publishing Co., 1904.) 



(4) The Theory of the Lead Accutnulator. By F. 

 Dolezalek. Translated by C. L. von Ende. Pp. 

 .\ii + 24i. (New York: John Wiley and Sons; 

 London : Chapman and Hall, Ltd., 1904.) Price 

 los. bd. net. 



(3) Electric Motors. By H. M. Hobart. Pp. x + 458. 

 (London : Whittaker and Co., 1904.) Price 12.S-. bd. 

 net. 



(6) Notices sur I'Electricit^. By A. Cornu. Pp. vii + 

 274. (Paris : Gauthier-Villars, 1904.) Price 5 

 francs. 



(7) L'Annee Technique (1902-1903). By .\. Da Cunha. 

 Pp. 303. (Paris : Librairie Gauthier-Villars, 1903.) 

 Price 3.50 francs. 



(i) A LTHOUGH wireless telegraphy is of such 

 •^». recent development, it is apparently regarded 

 by many as a legitimate subject for historical writing. 

 The first volume before us is one of several which have 

 appeared in the last three or four years in which the 

 historical progress of wireless telegraphy is dealt with 

 rather than its scientific principles. The book possesses 

 to our mind the same faults which characterise all the 

 other similar publications which we have read ; there 

 is a lack of discrimination in the selection of material 

 which is likely to leave the untechnical reader in a 

 state of considerable confusion. Wireless telegraphy 

 as we know it to-day is wholly concerned with Hertzian 

 wave telegraphy, and even if accounts of the experi- 

 ments of Lindsay and others in telegraphy by earth or 

 water conduction should be regarded as legitimate, we 

 NO. 1827, VOL. 71] 



cannot see by what possible stretch of the imagination 

 the achievements of, say, Marconi can be traced back 

 to the prophecies of Galileo in 1632. 



Mr. Sewall's method of compiling history appears 

 to consist chiefly in making extracts from patents. 

 Page after page of the book before us contains nothing 

 more than reprints from the patents of Lodge, Marconi, 

 Fessenden, and others, sometimes verbatim in inverted 

 commas, at others with slightly altered context 

 as original matter. We imagine it must be easier 

 to write books in this way than it is interesting to read 

 them. Mr. Sewall would have been much better 

 advised, we think, to digest his material properly and 

 present it to his readers in some more acceptable form. 

 He could then have given a connected account of the 

 remarkable developments that have followed the dis- 

 coveries of Maxwell and Hertz which would have been 

 of great practical use to students of the subject. .\t 

 present we doubt if his book is intelligible to the 

 amateur or useful to the expert. 



(2) The late Prof. S. Lemstrom occupied himself for 

 manv years with experiments on the effect of electricity 

 on growing plants, and this little book contains the 

 results of his work. If the conclusions at which the 

 author arrives are confirmed by the work of other in- 

 vestigators, the subject is one which merits the most 

 careful consideration by all agriculturists. Practically 

 only one type of experiment was tried ; an influence 

 machine was connected with one pole to earth and the 

 other to a wire network over a field in which the crops 

 were being grown. A discharge current could thus be 

 passed either from the network to earth or vice versa 

 for any desired number of hours a day. The experi- 

 ments were tried on a comparatively large scale in 

 several different localities. The effect produced by 

 this treatment was remarkable. There was an 

 average excess of the crop of the experimental field 

 over that of a control field of 45 per cent. ; the 

 excess varies considerably with the nature of 

 the crop and the conditions, soil, weather, &c. Not 

 only is this increase in quantity produced, but there is 

 also often an improvement in quality and a diminution 

 in the time taken for the plants to mature. This last 

 is a factor often of great importance to the grower, 



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