November 28, 1907J 



NA TURE 



a higher voltage than that usually employed in the Poulscn 

 system — 400 to 500 volts — may be found necessary, but 

 otherwise the apparatus installed does not differ very con- 

 siderably from that at other stations. A great many 

 improvements have been made in the different parts of 

 the apparatus since Mr. Poulsen gave a demonstration of 

 his system at the Queen's Hall, a full account of which 

 appeared in these columns at the time (Nature, vol. Ixxv., 

 pp. 105, 106), and the transmitter at Knockroe station has 

 been designed to transmit waves 3000 to 5000 metres 

 long, and capable of giving the desired wave-length with- 

 out any variation. The company has also a new thermo- 

 electric detector with which it expects to print Trans- 

 atlantic messages, and in consequence to be independent 

 of telephonic reception. The Poulsen-Pedersen " ticker " 

 method of reception also has been adapted to working a 

 relay and a Morse inker. This " ticker " receiver has 

 been greatly improved upon, and the latest form recently 

 established a long-distance record, receiving a ship signal 

 at a distance of 2060 miles. 



The theory of the formation of the rainbow has been 

 worked out more completely than hitherto by Prof. T. 

 Tanakadate in the August number of the Proceedings of 

 the Tokyo Mathematico-Physical Society. Taking account 

 of the loss of light on reflection and refraction, and of the 

 effect of polarisation, ihe author follows Airy*s treatment, 

 and obtains an expression for the intensity of light of each 

 of the four bows due to drops of a particular size, in a 

 form suitable for numerical calculation. 



In the Physical Review for October Prof. \V. S. 

 Franklin and Mr. L. A. Freudenberger describe an 

 arrangement they have found very satisfactory for measur- 

 ing the resistance of electrolytes without the use of 

 electrodes. The electrolyte is placed in an annular glass 

 tank which encircles the iron of a small transformer the 

 primary of which forms one arm of a resistance bridge. 

 In the corresponding arm of the bridge a similar trans- 

 former is placed, and the resistance of its secondary 

 adjusted until the bridge is balanced, when an alternating 

 current is supplied to it. The apparatus is so simple and 

 the results are so good that electrodeless methods should 

 replace some of those at present in use. 



The Physikalische Zcitschrift for October 24 contains 

 abstracts of many of the papers read at the Versammlung 

 deutscher Naturforscher und Aerzte in Dresden in 

 September. The meeting, owing largely to the exertions 

 of Prof. Hallwachs, was very successful. Of many papers 

 of great interest, two may be mentioned. Drs. E. 

 Gehrcke and O. Reichenheim have measured the change 

 of wave-length of the light of the anode rays when they 

 are seen end on, and have shown that when the anodi 

 is of sodium, lithium, or strontium the rays consist o 

 molecules of these metals thrown off from the anode 

 Drs. Scheel and Heuse have measured the expansion o 

 platinum between —183° C. and -(- 16° C, and find as the 

 mean result of three determinations by the two-microscope 

 method and by Fizeau's method 1602 X 10- ' cm. per centi- 

 metre. 



.Arrangements are being made by which the Proceedings 

 of the London Mathematical Society may be subscribed for 

 by the public at a uniform price per volume, the volumes 

 10 be supplied either in parts, as issued, or in volumes at 

 the option of the subscriber. The arrangement will begin 

 lo take effect with the next volume, the first part of 

 which will probably be published early in January, 1908. 



The Anglo-German Courier of November 23, published 

 by the African World, is entirely devoted to an illustrated 

 description in German and English of the recent visit of 



NO. 19S7. VOL. yy] 



the German Emperor and Empress to London. This is the 

 final number of that periodical, which was started to pro- 

 mote friendly feelings between the people of Great Britain 

 and Germany — a mission that may now be regarded as 

 accomplished. 



Two well-illustrated and conveniently arranged cata- 

 logues have been received from Messrs. Casella and Co. 

 One deals with self-recording instruments for scientific, 

 engineering, and industrial purposes, and the other pro- 

 vides descriptions of anemometers, air meters, and wind- 

 direction instruments. The catalogues deserve the atten- 

 tion of meteorologists, teachers of geography, and other 

 observers. 



A SECOND English edition, which has been re-written, of 

 Prof. A. F. Hollemann's "Text-book of Organic Chem- 

 istry," has been published in this country by Messrs. 

 Chapman and Hall, Ltd., and by Messrs. John Wiley and 

 Sons in New York. The first English edition was reviewed 

 in Nature of June 18, 1903 (vol. Ixviii., p. 149), and it 

 will suffice to say that the present volume is, like the 

 former, the translation of Dr. A. Jamieson Walker, and 

 is from the third Dutch edition. The translator has had 

 the cooperation of the author and the assistance of Dr. 

 Owen E. Mott. 



Messrs. J. M. Dent and Co. have published the fire; 

 number of the New Quarterly, a review of science and 

 literature, edited by Mr. Desmond MacCarthy. The price 

 of each issue is 2S. bd. net. If science is to receive the 

 same amount of attention in subsequent numbers, the 

 review should become popular in the scientific world. Of 

 the nine articles included in the present issue, four de.-l 

 with various departments of scientific work. Lord 

 Rayleigh, P.R.S., discusses the question, " How do wo 

 perceive the direction of sound? " The Hon. Bertrand 

 Russell writes on the study of mathematics ; the Hon. 

 R. J. Strutt, F.R.S., deals with the question. Can we 

 detect our drift through space? and Mr. G. A. Paley 

 contributes an article on biology and politics. 



OUR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in December : — 

 Dec. I. 2h. Mercury at greatest western elongation (20° 20'). 

 3. l8h. 30m. Mercury 4° W. from the Moon. 

 7. Iih. 42m. Minimum of Algol (18 Persei). 

 10-13. Epoch of the Geminid meteoric shower. 

 10. I7h. Mars in conjunction with Moon. (Mars 

 3° 25' S.). 



10. 8h. 31m. Minimum of Algol (3 Persei). 



11. 22h. Venus in conjunction with Uranus (Venus 



o°59'S.). . . 



12. 3h. 351T1. to 4h. 28ni. Moon occults 30 Piscium 



(mag. 47). 

 „ 5h. 28ni. to 6h. 42m. Moon occults 33 Piscium 

 (mag. 4-6). 



13. 5h. 20m. Minimum of Algol (B Persei). 



,, 3h. 54ni. to 4h. 44m. Moon occults 20 Ceti (mag. 



4'9)- 

 15. 2h. 55m. to 3h. 47m. Moon occults?- Ceti (mag. 



4'3)- 

 17. I2h. 53m. to I3h. iSm. Moon occults a' Tauri 



(mag. 3 '9). 

 ,, i I4h. 9ni. to I5h. i8m. Moon occults B^Tauri (mag. 



4"2). 

 20. 22h. Vesta in conjunction with ihe Moon. (Vesta 



0° 59' S.). 



22. I2h. Sun enters Capricornus. Winter commences. 



23. 2h 6m. Jupiter in conjunction with Mcon (Jupiter 



i'53'S.). 

 ^o. loh. 14111. Minimum of Algol {$ Persei). 

 31. 3h. Mars in conjunction with Saturn. (Mars 



1° 50' N.). 



