228 



NATURE 



[August 17, ign 



the map sheet would be painted on a house-roof or other 

 suitable surface, and this is considered more practical than 

 giving the name of the place. The projection employed is 

 the same as that of the international i : 1,000,000 map. 



\i 1 ORDING to the resume of communications made to the 

 Soci^tc; francaise de physique on July 7, M. M. Kernbaum 

 lias succeeded in showing that the " oxygenation " of 

 water, which two years ago he proved could be obtain'. 1 

 by allowing the ultra-violet rays from a mercury lamp to 

 act on the water, can be obtained from sunlight. Since it 

 is the ultra-violet rays which are effective, the action is 

 most marked at high altitudes, but it is large enough (o 

 be easily detected at sea-level if the water is in presence 

 of air. 



1\' a thesis submitted for doctor's degree in mathematical 

 science at Geneva, M. Hermann Streele, of Neuchatel, 

 dealing with the theory of mercurial compensation for 

 pendulums, suggests a new form of pendulum in which the 

 free surface of the mercury is near the middle of the 

 column, the upper part resembling a barometer tube. This 

 form, he claims, enables him to compensate theoretically 

 both the actual changes of temperature and the error due 

 to the want of uniformity of temperature in different parts 

 of the pendulum chamber. He follows Herr Wanach 

 fremembered as one of Prof. Albrecht's longitude observers) 

 in condemning the old approximate formulas of Lord 

 Grimthorpe and others, but apparently fails to realise the 

 great dependence of makers on " trial and error." He has 

 not completed the theoretical study, as he ignores, for 

 instance, any molecular temperature effect, and from the 

 practical point of view he has omitted any mention of 

 devices for keeping the atmospheric pressure nearly con- 

 stant. No hint is given of any possible application of 

 " invar " to mercurial pendulums, though its striking 

 success in bimetallic compensation would seem to recom- 

 mend a trial of this alloy for some part of the pendulum, if 

 not for the actual stalk. 



Extensive schemes of improvement of the docks of the 

 Port of London, forming part of a more extended scheme 

 resolved on some time nc;o, are now about to be carried 

 out at a cost of four millions of pounds. It is anticipated 

 that when these works are completed, they will be 

 sufficient to meet the needs of the port for several years. 

 The remainder of the proposed improvements will he 

 (lefen.d until the increase of trade renders them 

 necessary. The works now to be put in hand include 

 the construction of a new deep-water dock of sixty-five 

 It is anticipated that this will occupy five years, and 

 the estimated cost is 2,150,000?. This dock will be con- 

 structed to take vessels of considerably larger size than 

 those which now can find accommodation in the Thames, 

 iln depth being 38 feet and length of the lock 800 feet, or 

 250 feet longer than that of the present Albert lock. The 

 East and West India docks are to have their approach 

 widened to 80 feet, and depth increased to 31 feet, allowing 

 the entrance of vessels up to 9000 tons. The South-west 

 India dock and the London docks are to have new 

 entrances constructed, and to be otherwise made to meet 

 modern requirements. The water in the latter is to r-e 

 increased so as to make it q' feet above Trinity high-wate* 

 mark by means of a pumping installation. 



\ ci ISSIFIED lit "I new books anil new editions added 



wis's medical ami scientific circulating library, 1 |6 



Gower Street, W.C., .luring April, May, and June, just 



.I from Mr. Lewis, is :, useful catalogue of important 



Misled during that period. 

 NO. 2 1 8l, VOL. 87] 



OUR ASTRONOMICAL COl.l MN. 



Comet 191 iJ> (Kiess). — Observations of Kiess's comet, 

 made by Mr. Stratton with the Newall telescope on July 

 22, 25, and 26, showed a head some 3' in breadth, but 

 without any sharply defined nucleus. Mr. Newall, in No. 

 4517 of the Astronomische Nachrichten, does not give the 

 times of the observations, but states that the comet was 

 visible to the naked eye. 



Spectroscopic observations revealed a bright band at 

 X 516 in which the head was seen to be 5' or 6' broad, 

 and the band could also be traced along the tail to a 

 distance of at least 5' ; bands were also seen at \\ 474, 

 516, and 564, and the continuous spectrum was recorded as 

 very faint. 



A note appended to the ephemeris given in No. 43S of 

 The Observatory directs attention to the fact that on 

 September 3 the earth will pass through the point traversed 

 by the comet on August 7 ; a careful watch should be 

 kept for eometic debris in the form of meteors. 



Brooks's Comet, 1911c. — New elements and a ephemeris 

 for comet 1911c are published in No. 4517 of the Astro- 

 nomische Nachrichlen by Dr. Ebell. As the new positions, 

 especially for the later dates, show considerable departures 

 from those we reproduced in these columns on August 3, 

 we give the following abstract from the ephemeris : — 



Ephemeris (12/1. M.T. Berlin). 



.(true) 



i(true) 



1°K 1 



Aug. 16 



220 ... -30 335 ... 0-1932 ... 9-8632 ...8-5 

 4-3 . +43 6-8 ... 0-1747 ■■ 9^324 ••• S'j 

 ,, 24 .. 20 41-9 ... +40 438 ... 0-1552 ... 9-8033 ... So 



This comet was observed by Mr. Stratton on July 25 

 and 20, and was found to have a bright nucleus which 

 gave a continuous spectrum; the band at A 51b in the 

 spectrum could be traced faintly for about 2' from the 

 nucleus both towards the sun and in the opposite direc- 

 tion. The comet could be seen with a pai- of opera 

 glasses. 



A large number of observations of position and bright- 

 ness are recorded in the Astronomische Nachrichten (No. 

 4517) from Greenwich, Utrecht, Algiers, and many other 

 observatories. At Algiers Dr. Gonnessiat found, on 

 July 22, a 4' or 5' nebulosity having an eleventh-magnitude 

 nucleus which was not central. Herr G. van Biesbroeck 

 found that the magnitude of the comet seen with opera 

 glasses on July 20, 27, and 29 was about S-o. 



Encke's Comet, 191 id. — Dr. Gonnessiat's report of the 

 rediscovery of Encke's comet appears in No. 4517 of the 

 Astronomische Nachrichten, and states that the comet was 

 a difficult object in the dawn. Perihelion passage takes 

 place on August 19, and an ephemeris giving positions from 

 August 24 to September 21 appears in No. 438 of The 

 Observatory ; for August 24 and 28 the positions are 

 ioh. 44-5111., 5 46' N., and nh. i6-im., 1° 2' N., 

 respectively. 



The Observation of Meteors. — Amateur astronomers 

 not possessing efficient instrumental equipment cannot do 

 better than devote their attention to the observation 01 

 meteors, about which students of cosmogony still require 

 to learn many things. 



For such observers the publication {Observatory, No. 

 438) of a letter written by the late Prof. Alex. Herschel 

 to Mr. Denning in August, 1S76, is full of interest and 

 practical information. Those who had the pleasure of 

 corresponding with Prof. Herschel will understand that it 

 is impossible to describe a letter of his in detail in a con- 

 fined space, but the amateur will find especially interest- 

 ing the discussion of " trains." These phenomena are 



i.1,111 properly described, and Prof. Herschel takes some 

 pains to impress upon his correspondent the great import- 

 ance and the almost infinite variety of the luminous 

 phenomena attending a meteor flight. 



in i\ and Gamma Rays in Soi.ar Phenomena, — From Dr. 

 A. Brester, Jz., wi havi received an interesting mono- 

 graph dealing with the theory that solar phenomena are 

 produced by the solar emission of a and 7 rays. Dr. 

 Brestei starts with the terrestrial aurora produced by 



