April 1, 1807.] 



HAEDWICKE'S SCIENCE. GOSSIP. 



Halo bound Shadow. — I hare observed a 



phenomenon (and probably others have noticed the 

 same) which appears to me to be of interest, when 

 taken in connexion with the note in your January 

 number, entitled, " Halo of a Shadow," and with 

 two others in the succeeding number. If an in- 

 dividual stands in the rays of strong sun-light, his 

 shadow falling on a white ground, say a white 

 marble slab, the shadow will be seen to present 

 around, or without its margin, an appearance like 

 mist or smoke in motion, or rather of the shadow of 

 one or the other. The appearance is seen where 

 the naked body gives its shadow, and also in a less 

 degree where the shadow is cast from a portion of 

 the body covered with clothes. I myself have set 

 down this wavy or smoky appearance to the transpi- 

 ration from the skin, but am I right ?— R. G. 



The Phosphorescent Centipede. — "M. G. P." 

 asks the name of this. As I was coming home one 

 evening last August, I found several among the 

 herbage, and took one home. It proved to be that 

 represented in " Wood's Natural History," vol. iii., 

 p. 693, ArthronomaltiS longicornis. — Hy. Ullyett. 



Palse Hair as a Cause of Disease. — On 

 Thursday evening at the Harveian Society of Lon- 

 don, the scieutiiic points involved in the "chignon 

 question" were commented upon by Dr. Tilbury 

 Pox in a paper which had reference to the influence 

 of parasites in the production of diseased conditions 

 of the skin. It has been asserted, first, that false 

 hair contains the germs of pediculi, which are de- 

 veloped by the warmth supplied by the human 

 head; secondly that bodies called "gregarinae" 

 exist in false hair, and may become pediculi. The 

 first statement is wholly incorrect, but the so-called 

 "nits" are nothing but empty shells, whence the 

 young pediculi have escaped. The female pediculus 

 lays her ova at the part of the hair close to the 

 scalp; in six days the young are hatched, the 

 empty shell is carried forward by the growiug hair, 

 and as this is cut from the head at the distance of from 

 one to two inches, no true ova are brought away 

 with it. The inference is clear that no false hair 

 ever contains the materials from which pediculi 

 develop, and where these are present their exist- 

 ence must be accounted for by uncleanliness. The 

 second statement is equally untrue ; gregarines are 

 only found in Russian hair, which does not enter 

 the English market ; they have vegetable affinities, 

 and never give rise to any form of insect. In his 

 large experience of diseased states Dr. Pox stated 

 he had never seen them once on the hair. Lastly, 

 he described a real source of danger as yet unnoticed 

 by any observer. On some of the light brown or 

 reddish false hair of German origin, he had found a 

 species of " mildew " fungus, which unquestionably 

 would, if implanted upon the surface of weak per- 

 sons, give rise to "ringworm" and he produced 

 microscopic evidence and instanced cases in which 

 he had apparently seen mischief result in this way. 

 Cleanliness is a great preventive of evil, and such 

 hair should be subjected to proper processes to 

 insure protection against the production of disease. 

 While the great majority of the statements that 

 have been made recently about "chignons" are 

 wholly untrue and absurd, there is no doubting the 

 fact that without proper precaution the use of false 

 hair may give rise to certain uncomfortable con- 

 ditions of the part next which it is worn, but that 

 even this source of evil may be remedied. — Times, 

 March 9. 



Aquarium Pest. — My experience (of many years' 

 standing) with aquariums is that the snail spawn 

 does hatch, and the. young, if allowed, grow to a 

 good size, but with much thinner and brighter 

 shells than their pond relatives. Also that the 

 fishes, particularly the sticklebacks, do eat, not the 

 spawn, but the young snails, to an extent that 

 prevents most of them from arriving at maturity. 

 The jelly is sometimes gnawed in holes; I think 

 by the beetles. — Henry Faulkner, Jun. 



Aquarium Pest.— Can any of your numerous 

 correspondents suggest a plan by which the Aniscus 

 — an insect that devours the roots of the Valisneria 

 —can be destroyed without disturbing the aqua- 

 rium ? Do any of the smaller water-beetles feed 

 upon them? If so, what variety? Any prac- 

 tical suggestion will be thankfully received by 

 J. S. 



We have also received communications on this 

 subject from L. A. G. and H. M., which want of 

 space compels us to postpone. 



Waterton's Process. — Your correspondent 

 "H. M. G." will find this fully described in the last 

 edition of "Lee's Taxidermy" (Longman & Co.). 

 It is described as performed by Mr. Waterton him- 

 self in the presence of the writer. — Jas. W. Impey. 



Hyalodiscus. — I do not find that Pritcharcl 

 gives the pretty diatom, Hyalodiscus subtilis, var. 

 Icevis, as a British species. I find it in the washings 

 of weeds and stones, procured from under Bangor 

 Suspension Bridge. 1 have a slide to spare, and 

 shall be happy to send it, to any one who studies 

 their forms, through the Editor of Science-Gossip. 

 — R. G. 



The Rhythm of Plames. — In the Gossip for 

 last month there is an inaccuracy or an omission 

 which I wish to correct. A palm is assigned to Dr. 

 Tyndall, which he has not claimed for himself, and 

 which belongs to another. In the Philosophical 

 Magazine for February, Dr. Tyndall has published 

 an abstract of his lecture ; and in it he alludes to 

 Mr. Barrett (the lecturer on Experimental Science 

 at the International College) as having indepen- 

 dently observed not only the effect of sound upon 

 flames, but also the increase of light which accom- 

 panies the shortening of a flame by a musical 

 sound, and the superior effect of high notes. In 

 the same magazine for March, Mr. Barrett gives 

 the history of his discovery, and an account of his 

 experiments. He observed the extreme sensitive- 

 ness of a tall and tapering gas-flame while producing 

 the higher notes on a vibrating plate. He found 

 this flame shrank down several inches at a sharp 

 and shrill sound. Subsequently, having intensified 

 this phenomenon, he made a number of beautiful 

 experiments on similar flames. The jumping of a 

 fish-tail flame in response to musical sounds, an 

 effect the reverse of the above, had been observed 

 in 185S by Professor Leconte. To Leconte, there- 

 fore, is due the discovery of the spasmodic pro- 

 jection of tongues of flame by a fish-tail jet ; and 

 to Mr. Barrett we owe the observation of the 

 sensitiveness of a long and slender flame. In Mr. 

 Barrett's article above referred to, he says he was 

 made aware for the first time of Leconte's dis- 

 covery by the article of Dr. Tyndall. The discovery 

 may or may not lead to more important results, yet 

 to correct an inaccuracy so often repeated cannot 

 be unimportant. — R. W., Brixton. 



