June i8, 1908] 



NA TURE 



"57 



the properties of plain and hooped concrete. The addi- 

 tional strength of the hooped column over that for an un- 

 reinforced column of the same quality averages for eacli 

 1 per cent, of hooping 955 lb. per square inch for spiral 

 hooped columns and 669 lb. per square inch for band- 

 .hooped columns having a diameter of 12 inches. Tests 

 of a liquid-air plant are recorded by Mr. C. S. Hudson 

 and Mr. C. M. Garland (Bulletin No. 21). The tests were 

 made for the purpose of determining the most economical 

 conditions for operating the liquid-air plant belonging to 

 the University. 



We have received from the Rev. O. Fisher a letter 

 commenting on the distinction drawn by Mr. R. D. Old- 

 ham between " earthquakes " and " earthshakes " in a 

 coiTimunication published in the issue of Nature for 

 May 28. Mr. Oldham on that occasion wrote : — " We may 

 say that earthquakes, or at any rate severe earthquakes, 

 are frequently, if not invariably, caused by rupture of the 

 earth's crust' and the formation of fractures or faults in 

 the solid rock, but these fractures, which are the primary 

 cause of the earthquake, are only the secondary result of 

 the earthshake, the action of which arises at a greater 

 depth, and the ultimate cause of which lies beyond our 

 present ken " (vol. Ixxviii., p. 78). Mr. Fisher read this 

 to imply that Mr. Oldham applied the term " earthshake " 

 to the deep-seated cause of the " snap and jar " caused by 

 a rupture of the rocks, which gives rise to the vibratory 

 movement constituting an earthqualce, and suggests, as 

 more probable, that the deep-seated cause is of the nature 

 of an accumulating stress, which goes on increasing until 

 the crust gives way suddenly, producirjg the " snap and 

 jar " which produces world-shaking results. " What we 

 want," says Mr. Fisher, " is a term to express the molar 

 displacement of the ground as distinguished from the 

 vibratory." Mr. Oldham informs us that in reality he is 

 in agreement with Mr. Fisher. " The word earthshake," 

 he writes, " was not intended to apply to the slowly 

 accumulating stresses, but to the molar displacements 

 accompanying the abrupt relief of the strain induced by 

 these stresses." Mr. Oldhain says " it might have been 

 better to have suggested a wholly new word, such as 

 bathyseism, carrying with it no connotation of meaning, 

 but so inany ' seisms ' have already been suggested, and so 

 loosely used, that I was chary of inventing yet another." 



We have received from Prof. H. Mohn two valuable 

 publications relating to the meteorological service of 

 Norway for the year 1907 : — (i) the year-book, containing 

 complete .observations or results at sixty stations, and (2) 

 rainfall observations, containing daily measurements at 

 200 stations, with monthly or yearly amounts at a much 

 larger number of places, for some of which the results 

 are quoted so far back as 1867. These publications have 

 been issued in the same excellent form for many years, and 

 the data are of exceptional importance, due to the exposed 

 position and topographical features of the country. 



The report of the observatory department of the National 

 Physical Laboratory for the year 1907 shows that the only 

 very large magnetic disturbance was that of February 

 9-10, already referred to in N.4TURE (February 14, 1907, 

 vol. Ixxv., p. 367) ; the mean declination for the year 

 was 16° 23' W. The largest seismological disturbances 

 recorded took place on April 15 (the Mexican earth- 

 quake), maximum amplitude, 15 mm., September 2, and 

 December 30. The lowest temperature, 23°-3, occurred on 

 January 27, and the highest, 77°7, on September 25 ; the 

 total rainfall was 23-85 inches. The verification of instru- 

 ments (exclusive of watches and chronometers), one of the 



NO. 2016, VOL. 78] 



most active branches of the useful work of the observa- 

 tory, again shows a large increase, the total number of 

 instruments tested being 34,700, or 5133 more than 

 in the previous year, and was chiefly due to increased 

 numbers of clinical and ordinary thermometers. A large 

 part of the time devoted to experimental work has been 

 occupied by observations on atmospheric electricity and on 

 solar radiation. 



In Engineering of June 5 there is an illustrated article 

 on electric iron and steel furnaces, in which the leading 

 types are described. At the present time, electric iron 

 smelting is still in its infancy, while electric melting and 

 refining furnaces have been added to many notable works. 

 There is a good deal of electric melting, but, so far, little 

 smelting. The reasons are not far to seek. All furnaces 

 are wasteful ; the electric furnaces do not form an excep- 

 tion, and electricity is not inexpensive, whether generated 

 by water-power or by coal. The advantages of water- 

 power have been much over-rated. When water-power 

 begins to develop, it becomes subject to rates and taxes. 

 Hydro-electric installations are by no means simple. The 

 water may fail in summer owing to drought and in winter 

 owing to frost, and reserve steam-power has to be pro- 

 vided ; if a good load-factor is to be maintained, the reserve 

 must be of ample capacity. Manufacturers are, moreover, 

 becoming sceptical as to the advantages to be gained by 

 installing works close to the mines and to the waterfalls, 

 so as to secure cheap power and to avoid the transport of 

 ores. The power item is not, as a rule, the decisive factor, 

 and the crude ore transport may, after all, prove 

 economical. 



The practical value of the fascinating study of diatoms 

 as a test of the powers of the microscope is illustrated by 

 a note on Biddulphia mohiliensis contributed to the 

 .\pril Journal of the Royal Microscopical Society by Mr. 

 Edward M. Nelson. The secondary structure of this 

 diatom is so delicate that Mr. Nelson was unable to 

 draw or even retain the image for any length of time, 

 and in pointing out that the secondaries have only been 

 seen with long-tube microscopes, the author states as his 

 conclusion that " the ultimate appeal concerning any very 

 minute structure must go to a long-tube microscope." 



Prof. H. Fehr, editor of L'Enseigncment mathe- 

 matiquc, has reprinted from that journal the results of 

 his inquiry on the work of mathematicians. It will be 

 remembered that some time ago a circular was addressed 

 to matheinaticians containing thirty questions regarding 

 their habits of life, the way in which they acquired an 

 interest in mathematics, the advice they would give to a 

 young mathematician, and other matters of a personal 

 character. The classification of the answers has been 

 undertaken by Profs. Th. Flournoy and Ed. ClaparMe, 

 of the psychological department of the University of 

 Geneva. Perhaps the diversity of the answers is one of the 

 most noticeable features of the inquiry. 



.\ NEW periodical entitled Popular Electricity has just 

 been issued by the Electricity Publishing Co., of New 

 York. The -first number — for May — consists of thirty-six 

 well illustrated pages dealing with such subjects of general 

 interest as electric lighting in the house, how to read an 

 electricity meter, the new metallic filament lamps, &c. 

 The language is free from technicalities, and the treatment 

 humorous on occasions. It would be interesting to know 

 how far the electric milking machine and the electric 

 shoeblack described are commercially successful in 

 America. 



