46 



HA RD WICKE ' S S CIENCE- G OS SIP. 



A Curious Mouse. — A mouse was killed in a 

 field at Yatton (Somersetshire) in colour and size like 

 an ordinary mouse, except that the tail measured 

 only an inch in length, the head rather larger, and 

 the ears large and open, the curious and interesting 

 part being the mouth. From the upper jaw pro- 

 jected two tusk-like teeth curving inward towards 

 the mouth, and two much longer ones from the 

 centre of the under jaw, curving round one side of 

 the head. These last measured more than an inch 

 in length. Is not this something very unusual ? 



Dragon-Flies. — Your correspondent says, in 

 your issue of November i, under this heading : "I 

 have read of a Chinese dragon-fly with scarlet on the 

 wings, but never of a red-bodied English one." I 

 have often seen and taken adult males of the very 

 common Lihclhila striolata (Charp.), whose bodies 

 were of a beautiful orange-scarlet, the colour being 

 quite sufficiently pronounced to make the insect 

 appear bright red in the sunlight. Unfortunately, 

 the hue soon fades in the dried specimens, and it is 

 to me a matter of great regret that the colours of 

 these most beautiful insects cannot be more fully 

 retained. I would ask any of your correspondents 

 interested in this subject to favour your readers with 

 any hints as to their experience of the best way of 

 setting and preserving dragon-flies. — Abbott G. Laker. 



Fool's Parsley.^ — In the " Pharmaceutical Jour- 

 nal" for November 27, is an interesting article by 

 John Harley, M.D., in which the Fool's Parsley 

 (^Et/iiisa cyiiapiuiii) is declared and proved to be, not 

 only not poisonous, but a desirable herb for salad 

 purposes. I believe that the majority of botanists have 

 regarded this plant as very noxious, even dangerous. 

 Babington in his Manual says, "Herb poisonous." 

 Henfrey mentions it, in a list of the poisonous plants 

 of the Umbelliferce, in his "Elementary Course of 

 Botany," and other authors, too numerous to quote, 

 are unanimous in their opinions as to its baneful nature. 

 It certainly cannot be very active, as in one instance, 

 Dr. Harley gave as far as eight fluid ounces of the 

 expressed juice to a pSatient without any effect ; and 

 he chewed portions of the root himself with impunity. 

 Have any of your readers tested it, or experienced 

 any of its ill eff'ects "i—J. A. Wheldon. 



Anagallis C/Erulea. — I found one solitary plant 

 about six years ago, curious enough, in a shady part 

 of my garden (where ferns now grow) full in bloom. 

 I have never seen it since anywhere ; it never made 

 its appearance the year following. — J. IV., Tottenham. 



Sheet Lightning. — In reply to C. B.'s query 

 in a recent number on tliis subject, I offer him an 

 explanation thereon. First, the cause of sheet 

 lightning is electric discharges taking place between 

 clouds at such remote distances from each other as 

 to be below the horizon, and too far from the observer 

 to permit of the accompanying thunder being heard. 

 Hence the reason that thunder is very seldom heard 

 after this kind of lightning. Secondly, the diflerence 

 in shape between sheet and forked lightning is caused 

 by the resistance of the air, which varies in its 

 resisting powers, to the passage of the fluid to the 

 earth, or to another cloud, i. When the air offers 

 great resistance to the fluid ; it (in fluid) then takes 

 the course that offers least resistance to its passage, 

 and takes any shape to find those places. This would 

 be called forked lightning. 2. When the air offers 

 little or no resistance to its passage it takes a straight 

 and broad course. This would be called sheet 

 ligh tni ng. — Scientia. 



The Velocity of Sound in the Photophone. 

 — Can any of your scientific correspondents thrown 

 light upon this ? W^hat is the rate at which sound 

 travels in [the photophone ? W^e know that the 

 velocity of sound increases in proportion to the elas- 

 ticity of the medium through which it travels. Ether, 

 through which the waves of light undulate, must be 

 the most elastic medium with which we are ac- 

 quainted. Therefore are we justified in surmising 

 that sound can travel with the velocity of light ? Is 

 Professor Bell's discovery altogether new ? There is 

 something very like it in Dr. Tyndall's first lecture 

 upon sound. And in a note on p. 16 he writes, " It 

 is recorded that a bell placed on an eminence in 

 Heligoland failed, on account of its distance, to be 

 heard in the town. A parabolic reflector, placed 

 behind the beil so as to reflect the sound-waves in 

 the direction of the sloping street, caused the strokes 

 of the bell to be distinctly heard at all times." — 

 H.B.L. 



Preserying Crustacea. — I see that your cor- 

 respondent J. A. Wheldon uses corrosive subli- 

 mate in his process for the above. Now this is no 

 doubt a valuable preservative, but how does it 

 affect the colour? for bichloride of mercury would 

 certainly result in anything but a satisfactory way. On 

 the carbonate of lime of the carapaces of these 

 animals its effect would be to turn them yellow or 

 red, I think. — E. Lovett, Croydon. 



COMMENSALISM. (SCIENCE-GOSSIP, No. I92, 



p. 279). — .Such cases are not uncommon. Wagtails 

 are generally to be seen preying on flies as they settle 

 on cows feeding in fields, and nearly every flock, 

 of sheep round here is attended more or less by 

 starlings. — C. F., Eastbourne. 



DuLNE^S IN Objectives. — I observe in the 

 current (December) issue of Science-Gossip, a note 

 from Mr. W. G. W^oollcombe, intimating that he 

 has discovered the cause of the dimness of the field 

 of his 5 in., to be a film deposited on the surface 

 through changes of temperature, which requires to 

 be cleared off occasionally. It will, I apprehend, be 

 interesting to microscopists generally, but more espe- 

 cially to those who ventured to suggest a possible 

 cause of such dulness as he mentioned, to learn by 

 what process Mr. Woollcombe had revealed to him 

 its real cause. Would it not seem to be no more 

 than just to such as sought to help him out of 

 his difficulty, for Mr. W'oollcombe to give fuller 

 details of his discovery ? for at present there is an 

 apparent inconsistency between his statement of 

 the case in the May (iSSo) issue, and that which 

 now ajjpears in the December number of Science- 

 Gossip. In the May part, Mr. Woollcombe says : 

 " I have taken it (the objective) to pieces, and 

 rubbed it with chamois leather, but with no avail ;" 

 whilst in the current number (December) the 

 dulness is attributed to the fact that "changes of 

 temperature cause a film to be deposited on the 

 surface which requires to be cleaned off occasion- 

 ally." Now, Sir, if this last sentence of Mr. W^ooU- 

 combe's be an accurate statement of the fact, 

 there at once arises the question : "If the dulness 

 of the objective can be prevented by having its 

 surface occasionally wiped, why was the rubbing with 

 chamois leather of no avail ? " For the sake of 

 others who may be in a similar difficulty, I trust 

 Mr. Woollcombe will, at an early date, explain the 

 matter a little more fully than he has yet done. — 

 F. J as. George, Chorley, Lane. 



