July ;, 192 1] 



NATURE 



601 



series of manuals entitled " The Reconstructive 

 Technical Series," the aim of which is to diffuse 

 the new knowledge and enlarged technical skill 

 gained during recent years, and so to make it avail- 

 able for to-day as a means towards greater all-round 

 efficiency and increased competitive f>ower in the 

 world's markets. The first volume — " Engineering 

 Steels : An Exposition of the Properties of Steel for 

 Engineers and Users to Secure Economy in Working 

 and Efficiency of Result," by Dr. L. Aitchison — will 

 be published almost immediately. 



In recent correspondence on the subject of picture- 

 hanging wire, copper or brass wire has been recom- 

 mended." Mr. N. M. Richardson now writes to con- 

 demn these materials for this purpose on account of 

 the brittleness which develops in the course of a few 

 years. He advises the use of galvanised iron wire, 

 which can be painted a suitable colour if desired. Such 

 wire has been found to be very trustworthy and per- 

 maneflt unless it; is exposed to damp. 



Admirers of the late Sir William Abney will be 

 interested to learn that the Abney memorial lecture 

 by Mr. Chapman Jones (delivered before the Royal 

 Photographic Society of Great Britain on April 26 last) 

 is printed in full in the July issue of the Photographic 

 Journal. Copies of the journal are obtainable from 

 the publishers, Messrs. Harrison and Sons, Ltd., 45 St. 

 Martin's Lane, W.C.2, or the Societj^ 35 Russell 

 Square, W.C.i. 



We have received from Mr. R. S. Frampton, 

 37 Fonthill Road, N.4, a catalogue (No. 26, 192 1) of 

 second-hand books dealing with science — mainly 

 natural history and gardening. Some 1056 works are 

 listed, and the prices asked are low. The catalogue 

 is obtainable upon application to the bookseller. 



Messrs. George Bell and Sons, Ltd., announce 

 the publication by them in the autumn of a full report 

 of the proceedings of the Congress of the Universities 

 of the Empire now in progress. 



Our Astronomical Column. 



The Cape Observatory. — Expression is given by 

 Sir Joseph Larmor, in a letter to the Times of July 4, 

 to the apprehensions that are felt among- astronomers 

 as to the effect of the proposed transference of the 

 Cape Observatory from the Admiralty to the South 

 African Government. Judging by the condition of tht 

 Australian observatories, which at all stages of their 

 existence, and never more than at present, have been 

 greatly hampered through lack of -funds, the change 

 would not be to the advantage of astronomy. Further, 

 the suggested transfer would greatly weaken the close 

 bond of reciprocity that has from the first linked 

 the Greenwich and Cape Observatories. It is greatly 

 to be desired that the proposal, which would be little 

 sliort of a disaster to astronomy, may yet be averted. 



The Comet Pons-Winnecke. — This comet has now 

 passed out of sight of northern observers, but 

 ephemerides have been sent to southern observatories, 

 where it may be observed for two or three months 

 more. Mr. G. Merton has revised the orbit by using 

 observations extending from April 12 to June 2. He 

 finds 



T =1921 June 12-8985 G.M.T. 



« = 170'^ 12' 34'"! 



91-= 98' 12' 37" 1 1921-0 



/- 19° I' 7") 

 los a = 0-5295 7 



e =0'69242 



^ = 1-0411 



The most uncertain element is log a, for which the 

 above value is almost certainly too large. It gives a 

 period of 623 years, whereas the true value is unlikely 

 to exceed 593 years. But the other elements would 

 not be greatly altered by this change. 



Mr. Denning writes : — "On the night of June 28 I 

 saw some bright meteors, several of which presum- 

 ably belonged to the shower from Pons-Winnecke's 

 comet. It is desirable to procure duplicate observa- 

 tions of these objects if possible, for the purpose of 

 working out their real paths, and ascertaining whether 

 or not their radiant points nearly coincide with that 

 computed for the above comet. 



"The following are the times and apparent paths 

 of six of the more noteworthy meteors seen here, and 

 NO. 2697, "^OL. 107] 



if any of them have been observed elsewhere I shall 

 be very glad to receive such details as were recorded. 

 It need only be said with reference to the objects that 

 No. 4 in the list was a splendid fireball, and that 

 No. 5 is included on account of its exceedingly slow 

 motion. No. 2 was not accurately observed, owing to 

 its flight being partly intercepted bv a building. 

 Nos. I and 4 were directed from radiants far distant 

 from that of Pons-Winnecke. 



Meteors recorded Jane 28, 1921. 



No. G.M.T. Mag. From To Notes. Radiant 



n, m. o o o 



1 II 49 >^ 236 + 485 212 + 45i Rapid, streak 303 + 24 



2 II 56 >i 318- I 327- 7A Slow, white >R-W. 



3 1222 I 293+15 298+ 5 Slowish p -w 



4 13 18 5x9 339 + 3.3 348 H 18 Slow p..w' 



5 1330 2 311+67 330 + 61 Very, very slow P.-W' 



6 1334 11 319+194 312+ 2 Rapid, white 70 + 66 

 The Figure of the Earth.— An article on this sub- 

 ject by Prof. T. J. J. See (Astr. Nach., Nos. 5103-4) 

 IS interesting as an historical summary of the progress 

 of knowledge on the subject. Sir Isaac Newton recog- 

 nised that the compression was considerably less than 

 1/230, the figure for equilibrium with a homogeneous 

 fluid earth. The three chief methods have been 

 (i) the measurement of arcs of latitude, (2) lunar 

 perturbations, and (3) pendulum observations. In 

 1 75 1 La Condamine published the value 1/303-6 de 

 duced from measurement of arcs of latitude in France 

 and Peru. In 1802 Burg found the value 1/30505 from 

 method (2). These two values were surprisingly good 

 for that early period, but still not entitled to any 

 weight compared with modern determinations, 

 although Prof. See assigns some to them. The figure 

 1/293-465 was published bv Clarke in 1878 and 

 generally superseded Bessel's value of 1/299- 1^28 

 although the latter now appears to be closer to the 

 truth. In recent years methods (i) and (3), in the 

 hands of Helmert, Hayford, Bowie, and others, have 

 given very consistent results, from which the weighted 

 mean 1/298-3 is deduced. Prof. See gives a useful 

 table for obtaining geocentric latitude and radius 

 vector on this assumption, and notes that in his 

 opinion the value 1/294, adopted in Brown's Lunar 

 lables, IS decidedly too large. 



