knowli-.dgh;. 



Februakv, 191 ; 



Clusters and Nebulae. 



.ippcaiancc will probably be that of a few beads of 

 sunlight at the Moon's edge, not of a continuous ring. 



Tm-: Soi..\K Eci.iisL 01 .Vfuii, 17. — It will probabI\- be 

 convenient for those who propose to ^o to the central line in 

 this eclipse to have accurate information siillicifntly lon.i; 

 beforehand to make their arrangements. 



The following positions are based on a combination cif the 

 American Ephemeris with the Nautical .Almanac, going ,' of 

 the way from the former to the latter. (The reasons for 

 this course are given in the Journal of the H-.A.A. for 

 Decetnber.) T, A denote the probable durations of totality 

 or annularity. It should be noted that the phrase 

 " annularity " is really not suitable for l-'rance, :is the 



The track enters Portugal at Ovar, which was also on the 

 central line in 1900, when it was occupied by the Astronomer- 

 Royal, and many other English Astronomers. It passes 

 eighteen miles due east of Oporto, enters Spain near the 

 village of V'erin, in Orense, passes seven miles due east of 

 X'illafranca, in Leon, two miles east of Oviedo, and leaves the 

 peninsula some seven miles east of Gijon. According to the 

 above figures it wiil cease to be total while traversing the Bay 

 of Kiscay. It enters France six miles S.E. of Les Sables 

 d'Olonnc. in Vendee, passing fourteen miles south of Angers, 

 nineteen south of Le Mans (noted for aeroplane experiments), 

 through St. Germain en Lave, in the western environs of Paris, 

 very near N'amin- in Belgium, and onward into Germany and 

 Russia. Details for the partial eclipse in the British Isles 

 will l)e given next month. 



CORRESPONDENCE. 



SWEK PINGS. 

 I'd the Eilitors of " Knowledgi;." 



Sirs, — Mr. Enock ' evidently has misread Westwood's 

 "Introduction to the Modern Classification of Insects," or he 

 could not have written of Elcnchus tcniticurnis Teinpleton, 

 of which but one example had hitherto been recorded over 

 fifty years ago. In the text Wcstwood gives no author's name, 

 but in the synopsis bound up at the end of the volinne he 

 gives it correctly Elcnchus tcniciconiis K. .Moreover, in the 

 few pages in which he deals with Elcnclius and the other 

 genera in the order Strcpsiptern, he refers to specimens of 

 this insect having been taken by Stephens, Dale. Haliday 

 and Walker, in addition to that by Mr. Templeton (which he 

 (jueries as belonging to another species W'alkeri Curtis), and 

 although he does not expressly mention the insect, he was 

 obviously aware of the mutilated specimen on which Kirby 

 based his description in 1811. There are thus no less than 

 six separate and distinct captures of this species referred to 

 in the volume consulted by Mr. Enock. 



There has been considerable hesitation in admitting the 

 claims of E. Walkeri Curtis to rank as a distinctive species. 

 Mr. S. L.Saunders,in his monograph of ihi'Sf ylopidnc (Trans. 

 Ent. Soc, 1S72), queried it, but very properly divided the 

 records between the two species described, and the framers of 

 our lists, with one accord, have refused to admit more th.in one 

 distinct species, E. tennicornis K. In the latest monograph 

 of the Strcpsiplcra, written by W. 1). Pierce and published 

 this year in the "Genera Inscctoriini." the author elevates 

 E. Watlicri Curtis to specific r,ink. Me ,ilso adds the impor- 

 tant fact that " /:. tennicornis K. is known to be parasitic on 

 leaf-hoppers, prob.ibly of the genus I.iburnia." 



Mr. Enock is to be congratulated on his success after so 

 many years' search, and it may be that with this hint he will 

 be successful in elucidating still more of the life history of 

 these wonderful, minute p.arasites. 



B.VKNSLEV. E. G. B. 



ruE \i:l()City oi" light. 



To the Editors of " KNOWLEDGE." 



SiKS. — In the October ninnber of ''Knowledge "you kindly 

 published a letter from me suggesting that the Velocity of 

 Light, should be re-calculated from observations to be made 

 at dilTerent heights above the earth's surface, so as to see 

 what retardation, if any, is caused in the velocity of light by 

 the earth's atmosphere. My sug.gestion was founded on the 

 fact that we can see a flash of lightning, which apparently 

 usually passes from the thunder cloud to the earth; and 

 because the human eye is not capable of seeing juiything that 

 passes across its vision in less than about one-tenth of a 

 second, it seems to me that a flash of lightning takes more 

 than one-tenth of a second to pass from cloud to earth. 



.As a thunder-cloud is seldom at a greater height than two 

 miles above the earth, does not the flash of lightning take at 

 least one-tenth of a second to travel this distance r 



Mr. Charles E. Benham in the December number of 

 ■■ Knowledge," page 471, suggests that I was trying to hoax 

 your readers. Nothing was further from my thoughts, and I 

 will try to explain myself more thoroughly. 



The fil.unent of an electric light causes obstruction to the 

 current of electricity flowing from the generating station, and 

 the obstruction is so great that heat is generated and the 



In an .irticlu entitled " Sweepings," Knowledgi;, Volume xxxiv., page 400, Kigurc J w.ts by an accident l.-ibelled ■fem.ale," insto.iil 

 of male, after Mr. ICnock b.id p.issed liis proofs. Ki>s. 



