January i6, 19 13] 



NATURE 



551 



ing, of Kyoto, Japan, Mr. Takeo Wada examines these 

 and proposes a new definition of a simple curve, based, 

 like those of Veblen and Young, on the theory of sets 

 of points. It is shown that this definition of a curve 

 is equivalent to that of Jordan, and it appears in- 

 dependent of the dimensions of the space in which 

 the curve exists. 



Part 2 of vol. viii. of the Bulletin of the Bureau 

 of Standards contains a complete description of the 

 work done by Messrs. E. B. Rosa, N. E. Dorsey, 

 and J. M. Miller in determining the value of the 

 international ampere, which deposits I'liSoo milli- 

 grams of silver in one second, in terms of the abso- 

 lute ampere, which is one-tenth of a c.g.s. unit of 

 current on the electromagnetic system. The method 

 used is that of the Rayleigh current balance of the 

 single moving-coil type. The balance itself was a 

 30-cm. beam Rueprecht, from one pan of which the 

 moving coil was suspended between two coaxial fixed 

 coils. The coils were water-cooled so as to minimise 

 convection currents in the air. The ratio of the radii 

 of fixed and moving coils, 50 and 25 cm. respectively, 

 was found bv using them as concentric galvanometer 

 coils. The quantity directly measured by the authors 

 was the electromotive force in international volts at 

 the ends of a standard ohm carrying one absolute 

 ampere, but by comparing their result with that of 

 Messrs. Rosa, Vinal, and McDaniel, giving the inter- 

 national volts at the ends of the resistance when an 

 international ampere passed through it, they find that 

 the absolute ampere deposits i' 11804 milligrams as 

 against the international ampere, i' 11800 milligrams, 

 of silver in one second. 



The past year has been notable as regards the 

 smaller electrical apparatus in that great development 

 has taken place in domestic electrical appliances. Both 

 manufacturers and central station engineers have at 

 last awakened to the fact that in order to compete 

 with the gas companies in cooking and other appli- 

 ances an organised campaign is necessary to bring 

 before the public at large the advantages of the 

 smaller electrical domestic apparatus as produced at 

 the present time. Consequently the engineers of 

 municipal undertakings and supply companies have 

 been working hard to bring the hitherto comparatively 

 unknown domestic electrical appliances before their 

 consumers, and the manufacturers also by improved 

 and simplified heating units have largely contributed 

 to the success of this campaign. The present year 

 should see a reasonably cheap and economical electric 

 oven put on the market to compete with the everyday 

 gas cooker, which at present, on account of its low 

 initial cost, still holds the field against the electric 

 oven among the genera! public. Several English 

 manufacturers have also during the past year put 

 down extensive plant for the production of small 

 electric motors and fans, the greater part of which 

 up to quite recentiv were imported from Germany and 

 Italy. 



Reproductions from photographs of H.M. sub- 

 marine-boat E4 appear in both Engineering and The 

 Engineer for January 10. This boat is of the latest 



NO. 2255, VOL. go] 



type, constructed by Messrs. Vickers, Ltd., at Barrow- 

 in-Furness, and is of large size and great speed. The 

 surface speed of about sixteen knots is obtained from 

 heavy oil-engines of more than 1500 brake-horse- 

 power. It is understood that the vessel is nearly 

 i8o ft. in length and 23 ft. in beam ; the submerged 

 displacement is about Soo tons. A wireless telegraphy 

 mast is fitted, and there is a large rudder at deck 

 level, which improves the steering of the vessel when 

 submerged. It is also stated that the vessel accom- 

 modates disappearing guns. When travelling at the 

 surface, £4 draws about 12 ft. of water. Very little 

 authoritative information has been given regarding 

 vessels of the E class, for obvious reasons. 



The fortieth year of publication is reached by the 

 1913 issue of "Willing's Press Guide." The volume 

 provides an admirable index to the Press of the 

 United Kingdom, and useful lists of the principal 

 Colonial and foreign periodical publications. The 

 journals and proceedings of the various scientific 

 and other learned societies are duly indexed. 



The address on "The Place of Mathematics in 

 Engineering Practice," delivered by Sir William 

 White before the International Congress of Mathe- 

 maticians at Cambridge last August, and referred to 

 in our report of the proceedings of the congress 

 (September :;, vol. xc, p. 4), has been published in 

 full in our comprehensive contemporary. Scientia 

 (vol. xii., N. xxvi.-6), the London agents of which 

 are Messrs. Williams and Norgate. 



OUR ASTRONOMICAL COLUMN. 



The Sun's Magnetic Field. — The question of the 

 sun possessing a magnetic field, similar to the terres- 

 trial magnetic field, is discussed, especially with regard 

 to the phenomena of the sun's upper atmosphere, by 

 M. Deslandres, in No. 27 of the Comptes rendus 

 (December 30, 1912). He first discusses the matter 

 theoretically, and, supposing the magnetic field to be 

 produced by the rotation of the sun's electric charge, 

 shows that a solar ion expelled vertically from the 

 sun should be so deviated by the field as to describe a 

 helix having its axis parallel to the field; if many 

 luminous ions are expelled in the form of a promin- 

 ence the helical motion at the base of the promin- 

 ence, as seen from the earth, will depend upon the 

 position of the prominence in the solar magnetic field. 

 From a number of observations, M. Deslandres shows 

 that the recorded phenomena are in accordance with 

 the demands of the theory, and he accepts as certain 

 the existence of a general magnetic field about the 

 sun, similar to that of the earth, and in general much 

 more feeble. 



The Lxtegrated Spectrum of the Milkv Way. — 

 The Harvard analysis of the spatial distribution of 

 the spectra of more than 32,000 stars indicates that 

 the Sirian tj-pe predominates in the Milky Way, and 

 therefore the integrated spectrum of the galaxy should 

 be of the .A type. To test this conclusion Dr. Fath 

 has actually secured spectra of certain large areas of 

 the Milky Way, and finds that his results are not 

 exactly confirmatory. With the special spectrograph 

 he used for his work on the zodiacal light, he e.xposed 

 a plate for a total of 3oh. 20m. on the rich region of 

 the Milky Way that is partially bounded by the stars 

 7, S, and X Sagittarii ; a second plate was exposed for 

 a total of 65h., and gave better results. 



