\S2 



NA TURE 



[August 15, 1901 



ago, and circulars inviiing cooperation have been sent to 

 technical societies and engineers likely to assist the project with 

 suggestions and lists of words. Dr. Hubert Jansen has been 

 appointed editor of this " Technole.xicon," and an editorial 

 office has been established at Berlin (N. W. 7), 49, Dorotheen- 

 strasse. The dictionary will appear in three volumes, namely : 

 vol. I, German-English-French ; vol. 2, English-German- 

 French ; and vol. 3, French-German-English. To make the 

 work as complete as possible, it is hoped that many colla- 

 borators will collect technical words and expressions and send 

 to the editor those which do not occur in an ordinary dictionary. 

 A note-book for setting down such uncommon words and ex- 

 pressions which crop up in connection with engineering work 

 will be sent to persons who are willing to assist the project. 

 These words are acceptable even if the equivalents in the two 

 other languages are not known. The editor would also be glad 

 to receive references to, or copies of, good special dictionaries, 

 technological text-books, price-lists and catalogues referring to 

 any branches of industry or handicraft. We suggest that the 

 printed pocket-books used by electricians, engineers, surveyors, 

 architects and others contain a large number of technical terms 

 for which equivalents in French and German are difficult to 

 find. It is not clear from the prospectus whether the dictionary 

 will include technical terms used in physics and chemistrj' as 

 well as those which belong to engineering. If not, it will 

 sometimes be difficult to distinguish between scientific and 

 engineering terms. For instance, electrochemistry is an in- 

 dustry, so its technical terms will be included in the dictionary ; 

 but it is also a science, and its scientific terms should also be 

 included. If the scope of the dictionary is made sufficiently 

 broad to cover physical as well as engineering science, 

 the work should be of value to students of foreign scientific 

 literature. 



The Meleorologischt Zeitschrift for July contains a very in- 

 teresting and comprehensive article by Prof. H. Ebert, of 

 Munich, on the phenomena of atmospheric electricity, considered 

 from the standpoint of the theory of ions, or carriers of positive 

 and negative electricity, generated by the medium of radiation. 

 The electrification of a gas has, especially since the discovery of 

 theRontgen rays, become a subject of fundamental importance, 

 and has occupied the attention of several physicists, more par- 

 ticularly Messrs. Elster and Geitel, of Wolfenbtittel, and Mr. 

 Wilson, of Cambridge, who have independently arrived at impor- 

 tant and very similar results. They have also greatly improved 

 the necessary apparatus and methods of measurement, by w'hich 

 means they have been able to show the connection between the 

 electric conductibility of the air and artificially ionised gases. 

 The following are some of the results deduced from the ionic 

 theory, (i) The greater the solar radiation the less is the 

 electric potential generally observed. (2) The ions generated 

 at a great altitude are maintained for a certain time in the air 

 and participate in its movements. {3) Dust, and especially 

 aqueous vapour, obstruct the mobility of the ions, and therefore 

 diminishes the conductibility of the air. (4) Negative ions move 

 at greater speed than the positive. (5) The ions form conden- 

 sation nuclei which, in the case of supersaturated damp air, are 

 exhibited as fog or cloud ; hence the negative ions are more 

 suitable for forming nuclei than the positive. The subject of 

 the condensation properties of ionised air has been carefully 

 investigated by Mr. Wilson, and some of the results have been 

 published in the Philosophical Transactions and other scientific 

 papers. 



Mr. W. L. Moore, chief of the U.S. Weather Bureau, has 



given an official opinion upon the value of cannonading as a 



means of preventing the fall of hail. The following extracts 



from the Monthly Weather Reviexu show- that he does not 



NO. 1659, VOL. 64] 



attach any importance to the Stiger method of bombardment, 

 now so widely adopted in Italy, southern Austria and southern 

 France: — "It consists essentially in sending vortex rings of smoke 

 and air upward toward the clouds ; but the most powerful Stiger 

 cannon that have yet been employed do not send these rings 

 higher than 1200 feet above the ground, and, therefore, utterly 

 fail to reach the clouds. On this account the distinguished 

 Austrian meteorologist, J. M. Pernter, has maintained that if 

 there is any virtue whatever in the idea, the experimenters must 

 use much more powerful apparatus. But there is no satisfactory 

 evidence that the cannonading or the vortices had any influence 

 whatever on the hail. Both theory and practice agree in this 

 conclusion. Theoretically it was imagined by Mi. Stiger 

 that hail is formed in quiet spots in the atmosphere where the 

 atmospheric moisture could crystallise out in large crystals in a 

 manner analogous to the formation of large crystals of salt in 

 liquid solution. But this is a very foolish notion ; there are no 

 such quiet spots in the atmosphere, and hailstones are not crystals, 

 but masses of ice, with only a feeble or partial crystalline struc- 

 ture. Even the perfect crystals of the snow-flakes are formed in 

 the midst of rapidly-moving air, so that the whole theoretical 

 basis for hailstorm cannonading falls to the ground. . . . After 

 examining all that has been published duringjthe past two years, 

 my conviction is that we have here to do with a popular delusion 

 as remarkable as is the belief in the effect of the moon on the 

 weather. The uneducated peasantry of Europe seem to be look- 

 ing for something miraculous. They would rather believe in 

 cannonading as a means of protection and spend on it abundance 

 of money, time and labour, than adopt the very simple expedient 

 of mutual insurance against the losses that must inevitablv 



No. 169 of the Bulletin of the French Physical Societycontains 

 a brief note on some experiments by Mr. L. Benoist on the trans- 

 parency of bodies for Riintgen rays. The method adopted con- 

 sists in plotting curves in which abscissa: represent atomic 

 weights and ordinates represent the corresponding trans- 

 parencies. In this way it is possible to establish the existence 

 of a functional relation between the atomic weight and the 

 transparency, and, further, to discriminate between different kinds 

 of rays which give different curves. 



Bulletin No. 98 of the U.S. Department of .-Vgriculture con- 

 sists of reports by Drs. Atwater .and Sherman and by Mr. R. C. 

 Carpenter on food consumption and metabolism, and on the 

 mechanical efficiency of bicyclists. The experiments were made 

 during a six days' bicycle race, and consisted in analytical deter- 

 minations of the heat equivalent of the food consumed on the 

 one hand, and estimates of the work done as deduced from 

 calculations of air resistance and wheel resistance on the other 

 hand. The experiments show-, among other results, the great 

 amount of easily-digested food required by the competitors, the 

 greatly increased metabolism of nitrogen, the large amount of 

 work done per day by the athletes in this competition, which 

 averaged in one case more than ten million foot-pounds, or more 

 than five times the average daily work of a man as estimated by 

 Dr. Thurston, and, lastly, the high efficiency of the human subject 

 as a motor, for which the authors obtain estimates ranging as 

 high as 45 and 60 per cent. In regard to the accuracy of the 

 determinations, a good deal of uncertainty must exist as to the 

 amount of energy derived from combustion of body tissue by the 

 bicyclists, and also as to the actual resistance overcome, which 

 latter could best be determined by dynamometer observations. 

 The determinations of the efficiency of the human subject have 

 an interesting bearing on the question as to whether organic life 

 is subject to the second law of thermodynamics or ilaxwell's 

 "demons" actually exist in the animal kingdom. We should 



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