SCIENTIFIC NEAA^S. 



[May 2nd, 1887. 



lawn a piece of turf (six inches square and a quarter of an 

 inch in thiclcness), and placed it in a shallow pan, the 

 weight of the tuif and pan being carefully noted with a 

 sensitive balance. To prevent loss by evaporation, the 

 weighing was done in an open shed. The turf and pan 

 were then placed at sunset in the open cutting. Five hours 

 afterwards, when the turf and pan were weighed, it was 

 found that the turf had lost one hundred and forty-fifth 

 part of its weight, and the vapour which rose from the 

 ground during the formation of the dew accounted for this 

 difference of weight. Making both sets of experiments 

 on bare ground, he was even more successful, for there was 

 more condensed vapour inside the tray which was inverted 

 over the bare ground, than inside the one placed over grass 

 on the same night. It is also somewhat remarkable that 

 where the soil is thin, with a gravelly subsoil, farmers do 

 not remove all the stones ; but leave some to collect the 

 moisture. Around pieces of iron in the field, a very marked 

 increase of grass can be observed, owing to the deposit of 

 moisture near them. In these cases, also, the vapour rising 

 from the warm under-stratum is trapped by the cold surface- 

 earth, stones, and iron. As the warm vapour rises from 

 the heated earth it is trapped by the cold blades of grass, 

 and dew is formed. 



Mr. Aitken submitted his views to the Royal Society of 

 Edinburgh, when they were criticised by Sir William 

 Thomson, Professor Tait, Mr. Buchan, and Dr. Murray. 

 These eminent authorities came to the conclusion that this 

 new theory must take the place of the old. Since that time 

 there has been some discussion in the Philosophical 

 Magasine upon the subject, but the highest scientific authori- 

 ties in this country, and on the Continent, now admit the 

 truth of the conclusions to which Mr. Aitken has come. 



The theory of Wells, that the dew falls from the air above, 

 is therefore now untenable ; and Mr. Aitken has convinc- 

 ingly shown the correctness of the guess of Nardius, that dew 

 rises from the ground below. 



REVIEWS OF BOOKS. 



The Electric Moto?- and its Applications. By T. C. Martin and 

 J. Wetzler. New York: W. J. Johnston. 



This is a popular book on a subject which is of rapidly-growing 

 importance, both from a scientific and commercial point of view. 

 It is well printed, excellently illustrated, and brings before us, 

 in a way which must be startling to English readers who are 

 not well acquainted with the very recent applications of electricity 

 to motive purposes, the great and rapid strides which are being 

 made in this important direction. This progress is particularly 

 noticeable in the United States, where the readiness of the 

 people to make use of any new invention or promising applica- 

 tion, aided no doubt by favourable local conditions, has caused 

 quite a large number of electric railways and tramways to be 

 projected and put into operation. The action of the Americans 

 in this matter is only another instance of their enterprise and 

 keen perception of the useful. That it is not a case of superior 

 inventiveness is shown by the fact that almost, or quite, all the 

 real inventions and discoveries, and even the first practical 

 applications, are recorded as being European. But after having 

 brought matters to a state suitable for immediate application on 

 this side of the Atlantic, we seem to be advancing but slowly ; 

 while on the other side the advances are being pushed forward 

 with enthusiasm. 



Besides giving an account of all the important experiments in 

 electrical transmission of power and electric locomotion in 

 Europe and America, there are chapters of an introductory and 

 scientific character, interesting accounts of many ingenious 

 schemes which ante-dated the modern dynamo-electric machine, 

 and mainly on that account failed to obtain any success ; accounts 

 and illustrations of aerial navigation, and of " telpherage " — that 

 ingenious system which realizes in sober earnest the old joke 

 about sending articles by the telegraph wires — and, in fact, some- 

 thing about every proposed or consummated plan for making 



use of what has long been called "the motor of the future," but 

 which this book shows is, to a much greater extent than is as 

 yet understood by the general public, " the motor of the present." 



The Journal of the Iron and Steel Institute. No 2, 1886. 

 London : E. and F. N. Spon. 

 The ever-increasing bulk of the volumes comprising the 

 Journal of this Institute may be taken as fairly representa- 

 tive of its growing importance and prosperity. The present 

 issue contains, firstly, the full proceedings of the autumn 

 meeting, which, contrary to custom, was held last year in Lon- 

 don, no visit being made to the provinces during 1886. Eleven 

 papers were read, and discussed at greater or less length, and 

 everything that transpired is contained within the pages of the 

 Journal. When one remembers that many of the highest 

 authorities in the metallurgy of iron and steel, both from a 

 practical or manufacturing, and scientific and theoretical point of 

 view, take part in the meetings of the Iron and Steel Institute, it 

 is hardly necessary to point out the value of this book. In 

 addition to these papers and their discussions, there is the address 

 of the then President, Dr. Percy, who alluded to many points of 

 interest in his inaugural remarks. Amongst others were the 

 influence of chromium on steel, a subject then beginning to 

 attract that attention which it deserves. The mitis castings, 

 about which so much speculation arose when they were first 

 exhibited, a year or two ago, also gave occasion to some obser- 

 vations from Dr. Percy ; and the remarkable effect of a very 

 minute quantity of aluminium in an iron casting was dwelt upon 

 in this connection. Amongst the authors of papers we find the 

 names of Sir F. Abel, Colonel Maitland, Sir Henry Bessemer, 

 Percy Gilchrist, Edward Riley, Frederick Siemens, and F. 

 Gautier, besides others perhaps not quite so well known to the 

 general public, but possessing special knowledge upon some 

 subject of interest to the members of the Institute or the metal- 

 lurgical and mechanical world at large. A supplement, or second 

 division of the book, contains " Notes on the progress of the 

 Home and Foreign Iron and Steel Industries." These have been 

 culled from the various transactions and proceedings of foreign 

 scientific societies, or foreign technical journals and publications. 

 They appear to have been selected and edited with judgment 

 and care, and are arranged in sections convenient for reference. 

 On the whole, the present volume of proceedings may be said to 

 contain much valuable matter, well presented, and to be worthy 

 of a Society that does so much for that industry on which 

 Great Britain's commercial importance is more than all others 

 founded. 



Transactions of the Institution of Engineers and Shipbuilders in 

 Scotland. Thirtieth Session, 1886-87. 

 This issue of the transactions contains a farther instalment 

 of the adjourned discussion on Mr. Hector MacColl's paper on 

 the " Shafting of Screw Steamers," a paper on " Collision Pads 

 for the Prevention of Loss at Sea," by Mr. Richardson, and a 

 paper on "The Education of Engineers," by Mr. Henry Dyer, 

 M.A. 



The Watch and Clochmahers' Handbook, Dictionary, and Guide. 

 By F. J. Britten. London : W. Kent and Co. Price 5s. 

 We have received from the publishers this latest edition of 

 Mr. Britten's well-known book. Some new features appear to 

 have been introduced in the general arrangement of matter in 

 order to facilitate reference. The work may be described as an 

 encyclopedia of watch and clock making, to which has been 

 added the French and German equivalents of the terms used. 

 The author does not, however, confine himself to a list and 

 description of the various parts of time-keepers, the tools and 

 appliances used in their manufacture, etc., but gives also descrip- 

 tions of some of the processes employed in the production of 

 watches and clocks. The value of the book is much enhanced 

 by the large number of useful engravings, and a serviceable ap- 

 pendix is added. 



The Council of the Royal Society have decided that the pub- 

 lication of the " Philosophical Transactions " shall henceforth 

 be in two independent series, one ia) containing those papers 

 which are of a mathematical or physical character, the other 

 (b) those of a biological character. The papers in each series 

 will form a yearly volume ; and that each paper shall be also 

 issued separately in paper covers as soon as it is ready for 

 publication. 



