112 



KNOWLEDGE. 



[May 1, 1896. 



Imect Life. By Frod. V. Theobald, IM.A., F.E.8. 

 (Metliuen.) Illustratod. This book, which is one of the 

 University l''xtension Series, sets forth very clearly and con- 

 cisely tlie chief characteristics and economic importance of 

 the different orders of insects. It also deals with the life 

 history and structure of many interesting species. Two 

 useful appendices are added, the one on different ways 

 of destroying insect pests, while the other comprises a list 

 of the most important works on special groups of insects. 

 Mr. Theobald's book will be found of groat use to those 

 who want to gain a general knowledge of insect life. 



BOOKS EECEIVED. 



Text-boot of Comparative Anatomy. By Dr. Arnold Liing. 

 Translated by"]!. M. Bernard, M.A., and Matilda lievnard. Part II. 

 (Mneniillan.) lllustnitcd. 17s. net. 



The Astronomii of Milton's " I'aradixe Lost!' By Thomas N. 

 Orchard, M.D. (Longmans.) Illustrated. \h%. 



British Hea Birds. By Charles Dixon. (Bliss, Sands, & Foster.) 

 Illustrated. 10s. 6d. 



A Handlionk to the Birds of Great Britain. By B. Bondlcr 

 Sharpe, LL.D. Vol. Til. (Allen.) Illustratod. 68. 



Our Countrt/'s Butter/ties and Moths. By W. J. Q-ordon. (Day 

 & Son.) Illustrated, (is. 



Historical and Future Kclipses. By Rey. S. J. Johnson, M.A., 

 F.R.A.S. New ICdition. (Parker & Co.") Illustrated 4s. 6d. 



The Composition of E-rpired Air and its Elfects upon Animal 

 Life. By J. S. Billings, M.D., S. Weir Mitchell, M.D., and D. H. 

 Bergey, JI.D. (Washington : Smithsonian Institute.) 



A Lnloratorji Notebook of Jilementan/ Practical Fhi/sics. By 

 L. R. Wilberforeo, M.A., and T. C. Fitzpatrick, M.A. (Cambridge 

 ITniyersity Press.) Is. 



•Tames Clerk Maxwell and Modern Phi/sics. By R. T. Grlazebrook, 

 F.B.S. (Cassell.) The Century Science Series. Illustrated. 3s. 6d. 



[The ^Editors do not hold themselyes responsible for the opinions or 

 statements of correspondents.] 



ELECTROGRAPnY. 

 To the Editors of Knowledge. 



SiES, — I read Mr. J. W. Giflbrd's article on electro- 

 graphy in the April Number of Knowledge with great 

 interest. I should, however, like to draw your readers' 

 attention to the fact that the electrician Hertz, mentioned 

 in this article, was not a Swiss but a great German 

 professor. 



He was born on February 22nd, 1857, in Hamburg, 

 and after having studied in Jlimich and Berlin (under 

 Helmholtz) he became, in 1885, Professor of Physiology in 

 Karlsruhe, and followed Clausius in 1889 at Bonn, where 

 he died on January 1st, 1894, after a short but brilliant 

 career. 



North Woolwich. E. Wohlwill. 



ZODIACAL LIGHT (?). 

 To the Editors of Knowledge. 

 Sirs, — Your correspondent, Mr. Lyon Browne, will find 

 a very similar appearance to that seen by him on the 4th 

 of March described as seen by Dr. Brauner, of Prague, on 

 the 13th of the same month, in Nrrturr for March 28th, 

 except that Dr. Brauner saw five streaks instead of one. 

 And if he will refer to Knowledge for 1883 he will find 

 similar appearances described by Captain Noble and Mr. 

 Bradgate as seen by them (at different hours) on the night 

 of August 28th, 1883, and by Mrs. Harbin on September 

 21st, 1883, except that these appearances were in the 

 eastern, not the western, horizon. I saw a similar appear- 

 ance in the east on the 4th of September, 1885. The 

 phenomenon appears to have been taken on other occasions 

 for a comet or comet's tail by Mr. Eddie, at (Trahamstown, 

 and by Mr. Edwin Holmes ; and a similar mistake seems 

 to have occurred so far back as the year 1761, judging from 



the Annual. Eajister of that year. By others (myself 

 included) it has been mistalcon for a meteor or meteor- 

 track, but its real character has yet to be explained. 

 Possibly it is more akin to the Aurora Borealis than to 

 comets, meteors, or the zodiacal light. It would be 

 interesting to know whether there were any electric or 

 magnetic disturbances on the nights when it has been 

 noticed, of which we may safely set down August 28tli and 

 September 21st, 1883, September 4th, 1S85, and March 

 4th and 13th, 189(i. It seems to appear in the east in 

 autumn and in the west in spring, if we may judge from 

 the few observations that I have been able to collect. 

 Perhaps sonic of your readers may be able to add others. 



W. H. S. MoNCK. 

 — .-•-. — 



To till' Kditors of Knowledge. 



Sirs, — I also saw the phenomenon described by Mr. 

 Lyon Browne in the April Number of Knowledge. It was 

 about 8.55 p.m. when I first noticed an unusual streak of 

 light in the west. I watched it with a field-gliiss for 

 quite twenty minutes. At 9.20 it had become exceedingly 

 faint and ill-defined, and a few minutes afterwards had 

 disappeared. It appeared to me a broad column of light, 

 sloping towards the south at an angle of about sixty degrees 

 with the horizon. Its base was (as your correspondent 

 states) about five degrees in width, and appeared to spring 

 from a bank of clouds low down. From this base the light 

 extended upwards about twenty or twenty-five degrees, 

 tapering gradually to a point, which, however, was very 

 faint and indefinite. The margins of the light were fairly 

 distinct. The said margins appeared to be very slightly 

 curved, so that the light had the shape of a spear-head, or, 

 more exactly, the outline of the section of a thin double 

 convex lens. Its brightness was considerable. It was 

 much brii/hter than the MilJnj Way, and looked more like 

 moonlight when it struggles through cloud or mist. I am 

 not quite certain that it moved slightly towards the south, 

 but I am quite sure that at nine o'clock its northern border 

 towards the apex was nearly touching two bright stars near 

 together and below the Pleiades, but that about ten minutes 

 later it was two or three times its own diameter to the south 

 of them. Now what was this light '? 



I see that someone writes to the English Mechanic 

 confidently describing it as an " auroral streamer." I 

 have seen Aurora frequently, but never like this. On the 

 other hand I have never been able to see the zodiacal 

 light, which is always described as very faint and difficult 

 to observe, so that I could hardly believe I was actually 

 beholding that difficult object. And yet its shape, position, 

 and inclination ? 



Iron Bridge, Salop. T. Law Webb, M.R.C.S. 



27th March, 189G. 



— i * I 

 To the Editors of Knowledge. 

 Sirs, — I should like to say a few words in reference to 

 the " unusual phenomenon " observed on March 4th, and 

 described by Mr. W. L. Browne, jim., in your April 

 Number. I feel no doubt in my own mind that it was 

 an auroral streamer, an impression confirmed by two 

 letters in the Ew/lish Mechanic. My attention was called 

 to it here at 9.15, shortly before it faded away, but it was 

 visible for about an hour previously. Had I been able to 

 watch it from the first I might have detected some motion. 

 At 9.15 it was nearly due west, the sky being cloudless, 

 with a little mist on the horizon. I find that it was noticed 

 in other places in England, and that a discussion took 

 place at the meeting of the Eoyal Astronomical Society on 

 the 13th as to its nature. I may add, as confirming my 

 own conviction, that it singularly resembled a beam of 

 light which I observed last year in nearly the same 



