82 



SCIENCE- GOSSIP. 



Spider new to Britain. — Adult specimens of 

 both sexes of an interesting spicier, apparently 

 new to the British fauna, were taken by myself 

 under decaying boards in a summerhouse at 

 15 Cloudesley Place, London. The species appears 

 identical with Tapinocyba parisiensis Simon, the 

 Rev. 0. P. Cambridge expressing an opinion that 

 it is so ; but as it does not exactly coincide with 

 Mons. Simon's description in a few minute details, 

 I have thought it advisable to defer any descrip- 

 tion until I am convinced that these minutiae are 

 not of specific importance. — Frank P. Smith, 

 15 Cloudesley Place, London, N. 



A rare Spider. — I have just received for in- 

 spection a living female of Toxeus formicarius Wlk. 

 (Salticus formicarius Bl. and Cb.). The specimen 

 was procured from Yaxley Fen by the Rev. H. P. B. 

 Chubb, who informs me that he has since taken a 

 male in the same locality. I have but four previous 

 records of the occurrence of this spider in Britain, 

 so that it cannot be regarded other than as a great 

 prize. It is undoubtedly the finest example of 

 protective resemblance which we have amongst 

 our indigenous spiders, bearing a most striking 

 likeness to an ant, and the deception is greatly 

 heightened by the creature's curious gait. The in- 

 dividual which I examined evinced but little desire 

 to jump — in fact, practically refused to do so — but 

 this may be due in some measure to its confine- 

 ment for a considerable time in a glass-topped 

 box, its early attempts having, perhaps, resulted in 

 a collision between itself and the glass. I have 

 been recently informed by the owner of a " troupe " 

 of performing fleas that a similar method was 

 adopted to persuade these nimble little insects to 

 relinquish the luxury of saltatorial progression. — 

 Prank P. Smith, 15 Cloudesley Place, London, N., 

 July 1901. 



Dark Lightning Flashes. — During the great 

 thunderstorm, which lasted -with us for twenty 

 hours, on the night of June 30th last, and covered 

 the whole of the South of England, I observed 

 among the almost incessant bright flashes some 

 that were apparently dark, or even black. Is not 

 this very unusual 1 They were in form much as 

 ordinary lightning. My point of view was easterly 

 from my bedroom window, overlooking our coast- 

 line and the sea. — C. A. Brlggs, Hock House, Lyn- 

 mouth, North Devon, July, 1901. 



[Writing to " Nature,'" August 10th, 1899, Lord 

 Kelvin drew attention to this phenomenon, and 

 attributed it to optical illusion, as he got the 

 same effect on the wall of his room when he turned 

 his face from the window. Other correspondents 

 to our contemporary gave similar experiences, and 

 attributed it to fatigue of the retina. However, at 

 p. 423 of vol. lx. Mr. Alex. Morton, secretary of the 

 Royal Society of Tasmania, supplied a photograph 

 of a ribbon-like flash taken by Mr. W. Aiken, show- 

 ing numerous faint but dark flashes springing from 

 the main current. This was attributed to a trick 



of the photographic plate, and not an actual re- 

 presentation of what took place. Photography 

 thus gives no support to the view that dark light- 

 ning has a real physical existence, as the same 

 effect can be artificially obtained in a room when 

 photographing the discharge of an electrical 

 machine. It is due to what is technically called 

 " photographic reversal." At p. 570 of the same 

 volume of " Nature " Dr. William J. S. Lockyer 

 contributes a remarkable article, with six striking 

 illustrations. In this communication he says that, 

 though retina fatigue does doubtless reproduce 

 dark images of past flashes, " it does not necessarily 

 follow that dark flashes do not actually occur." 

 He refers to Mr. Clayden's experiments, who claims 

 to have cleared up the whole subject, and describes 

 the origin of the images of black flashes on photo- 

 graphic plates as being only a question of exposure. 

 Dr. Lockyer further gives the results of experiments 

 which show that by varying the intensities of the 

 sparks (= flashes) and the illuminated background 

 one can produce any combination of dark or bright 

 flashes. We may therefore take it that there is no 

 such actual physical phenomenon as black light- 

 ning.— Ed. S.-G.] 



Ixodes Hexagonus in Human Arm. — Dr. 

 Fowler, of Epping, recently sent to us for identi- 

 fication a female specimen of this tick fully 

 distended. He was attending a farmer's wife who 

 was suffering from a painful swelling in the arm. 

 After some probing this female tick was dis- 

 lodged. Mr. Wheler, whose interesting articles on 

 these animals are now appearing in this magazine, 

 stated, on the specimen being sent to him, that it 

 was one of the most common forms of sheep tick, 

 and had been occasionally found in the human body. 

 Mr. Wheler kindly mounted it, so that oviposition 

 could be observed under the microscope. Some 

 clays after removal from the woman's arm it was 

 still depositing eggs at intervals. This species is 

 fully described by Mr. Wheler on p. 40 ante. 



The Museums Journal.— We welcome a new 

 organ published in the interests of what should 

 now rank as a profession, the curatorship of our 

 public and private museums. That the occupation 

 is scientific is self-evident, and, like other profes- 

 sions that rank as such, will take the title when 

 the curators are strong enough to organise their 

 body and obtain for themselves a charter. This 

 journal is a step in the direction indicated, and 

 cannot fail to form another link in the bond of 

 brotherhood. The first 'number is embellished with 

 a portrait of Sir William Turner, K.C.B., F.R.S., 

 the President of the Museums Association for 

 1901. The first article deals with the Museums 

 Association, and this, its journal. It is, as might 

 be expected, an appeal to everyone connected with 

 museums, or interested in such institutions, for 

 support to this new organ. It is most desirable 

 that this should be given, when one remembers the 

 want of uniformity and general ability displayed in 

 the management of most of our country museums. 

 The second is a report and address by the President 

 of the Edinburgh Conference of this year. Then 

 follows useful and general notes. The journal is 

 edited by Mr. E. Howarth, F.R.A.S., assisted bv 

 W. E. Hoyle, M.A.,andF. A. Bather, M. A., D.Sc, in 

 England; B. Meyer, M.D., Germany; F. A. Lucas, 

 United States ; B. H. Woodward, F.G.S., Australia ; 

 W. L. Sclater, South Africa ; and Captain F. W. 

 Hutton, New Zealand. Price Is. net. 



