June 19, 1885.] 



♦ KNOWLEDGE • 



533 



piece of paper in from of him. It is important tliat A sUouUl uot 

 watch B's performance. 



If B.'s diagram in a number of instances strongly resembles A.'s, 

 we hare a Terr strong indication that B.'s impression was dno to 

 the idea in A.'s mind. (See especially the examples engraved in 

 the Proceedings of the S.P.R., Part V., 33-42, and Prof. Oliver 

 Lodge's paper on the subject, Pan VI. p. ISO.) 



I shall be most grateful to any of your readers who will make 

 experiments of the types described. The results should be sent to 

 me at 14, Deans-yard, S.W. In the card experiments, negative 

 results — i.e., cases where the total of right guesses has not exceeded 

 250 out of the 1,000 trials — should, of course, be sent as well aa 

 positive. Edmund Gcrxey, 



Hon. Sec. for the Society of Psychical Research. 



A PARADOX. 



[1772] — It has often been said, " There is nothing so false as 

 facts, except figures." Now here I send you a paradox involving 

 both facts and figures, and I have never yet met with any ono 

 who could give me a satisfactory explanation of tho contradiction 

 involved in it. 



We say every child has two grandfathers, four great-grand- 

 fathers, and eight great-great-grandfathers, and so on. Now wo 

 have only to carry the compntation back a few hundred genera- 

 tions, and to furnish these ancestors we should require a popula- 

 tion greater than could possibly have existed on the earth at one 

 time. 



Again, suppose I and my wife, and my friend Jones and his wife, 

 emigrate to an uninhabited island and colonise it. Our grand- 

 children will each have two grandfathers, and our great-grand- 

 children ought to have four great-grandfathers ; but in actual fact 

 they have only two, viz., myself and Jones. Our great-great- 

 chiidren'will require each eight great-great-grandfathers, but in fact 

 have only two. Can any of your readers explain how it is that 

 fact and theory so flatly contradict each other ? Coleford. 



THE GEOLOGY OF CHARNWOOD FOREST. 



[1773] — Several friends and myself have been induced by Mr. 

 Harrison's interesting papers to pay several visits to this instruc- 

 tive geological district. In Brazil Wood, we found what appeared 

 to be the junction between the syenite and the slate, mentioned 

 by Mr. Harrison. We could only find one quarry in the wood, in 

 the only section of which we found the apparent junction. Would 

 Mr. Harrison kindly say if this would be the one which he men- 

 tions. Certainly in this section we saw a coarsely crystalline 

 rock (presumably the syenite), passing into a finely crystalline 

 knd then into a slaty-schistose rock, and this within the range of 

 a few feet. In a single specimen which I obtained there is a well- 

 marked gradation from a coarse to a finely crystalline rock. 



On the ridge overlooking the quarry at Mount Sorrel there is a 

 section exposing the granite, which has "weathered " to a depth 

 of ten or more feet. Overlying this there is a layer of subsoil, and 

 over this a stratum of pebbles and gravel, in the lower portion of 

 which we found a number of fragments of bones and nnglazed 

 earthenware and tiles (the latter from an inch to an inch and a 

 quarter in thickness) which do not appear to be modern. There is 

 some six inches of subsoil overlying this bed. We are somewhat 

 puzzled how to account for this occurrence of pebbles and gravel. 

 Has Mr. Harrison noticed the section, and if so, would he kindly 

 favour us with his opinion. Geo. Fletchek. 



PHOSPHORESCENCE. 



[1774] — ^Near to my house there is an avenue of lime-trees, the 

 growth of which is so luxuriant that the foliage almost shuts out 

 5ie direct rays of light, and in this avenue, at half-past ten last 

 night, I noticed a phenomenon that you may esteem worthy of 

 chronicling. 



The direction of my walk was northerly, and I noticed that the 

 leaves, and the air in their vicinity, were suffused with a soft, faint, 

 phosphorescent light. This for a time I attributed to the vapour 

 from the wet leaves being illuminated by the moonlit clouds at my 

 back, but, to settle my doubts, I examined a dense mass of trees 

 from their shady side, and found the light still distinctly visible, 

 bnt, I think, not attributable to the moon. 



I believe some flowers are said to emit light. Are trees known 

 to possess this power, and have the causes been unravelled ? 



A. S. Babxes. 



THE UEKMESTES. 



[1775]— In connection with Mr. E. A. Butler's article on tho 

 " Dermostida^" I think that somo of your readers may find to bo 

 interesting tho enclosed extract from O. W. Holmes's " Poot at 

 tho Breakfast-table " : — 



" ' Will you lot mo look at that book a single minute ? ' said tho 

 Scaraboe. 



" I passed it to him, wondering what iu tho world ho wanted of 

 ' Paradise Lost.' 



" ' Dermestcs lardarius,' ho said, pointing to a placo where tho 

 edge of one side of tlio outer cover had boc-n slightly tasted by some 

 insect. ' Very fond of leather while they're in tho larva state.' 



" ' Damage the goods as bad as mice," said the salesman.' 



" ' Eat half tho binding off folio 07,' said the Registrar of Deeds. 

 ' Something did, anyhow, and it wasn't mice. Found tho shelf 

 covered with little hairy cases belonging to something or other that 

 had no business there.' 



" ' Skins of the Dermexte.f lardarins,' said tho Scarabee. You 

 can always tell them by those brown hairy coats. That's the name 

 to give them.' 



" ' What good does it do to give 'em a name after they've eat tho 

 binding off my folios ? ' asked the Registrar of Deeds. 



" Tho Scarabee had too much respect for science to answer such 

 a question as that." C. F. Clarke. 



OIL-GLANDS OF THE DUCK. 



[1776]— In the article on " Philosophy of Clothing," page 451 of 

 the present volume of Knowledge, Mr.WiUiams says of ducks : — 

 " And I have read accounts of special oil-glands with %vhich the 

 animal is said to bo sujiplied, and by means of which it oils its 

 feathers in order to keep the water from wetting them." Can he 

 doubt the fact ? If so, I would recommend him to study tho 

 anatomy and habits, &c., of the duck, and more especially the 

 beautiful articulation of tho bones of the neck, after whiL-h I should 

 imagine that Mr. Williams's remark about " a paint brush for them 

 to oil their feathers," Ac, would become quite superfluous. There 

 is positively no "amount of learned pretention" required on the 

 part of any one to prove tho fact of the existence of oil-glands in 

 all the duck family, and their method of distributing the oil on the 

 feathers of the body. The whole paragraph suggests the idea that 

 the writer is far more familiur with the bird when nicely browned 

 fresh from the oven than when in her pristine condition. — G. A. 



'DE GUSTIBUS." 



[1777] — Please allow me to assure " An Old Draughtsman," 

 that there was not the faintest particle of dynamite about my 

 letter (1709). The only movement it was commissioned to convey 

 was the very gentlest ripple. Although Fig. 9 does not show one 

 of the commonest shapes for a picture-frame, still it is a form with 

 which we are suSiciently familiar in the case of doors, windows, 

 panels, niches, &c. Is it intended to be understood that the form 

 shown in Fig. 10 is objectionable because of its rarity ? Perhaps 

 the owner of the glass could give a very satisfactory reason why 

 he preferred to see it placed like Fig. 11, instead of like Fig. 12. 

 I am sorry to have to differ from " An Old Draughtsman " as to 

 the construction in Fig. 13. A building is not bound to bo con- 

 Btruotionally good because it does not fall down. For instance, 

 it is quite possible to build a tall chimney so that it will seem at 

 a considerable angle (in fact, many tall chimneys arrange that for 

 themselves), and although that might be considered a tour de 

 force, still it would be better construction to make it perpen- 

 dicular. 



Pardon my directing attention to the fact that in my comments 

 on Fig. 5, I did instance a very old recognised class. 



I quite agree with " An Old Draughtsman," that a chief source 

 of the difficulty in investigating questions of taste lies in the 

 confusion of the separate elements in the question. The fruits of 

 the toil of many workers will have to be gathered yet before those 

 elements can be sufficiently sorted out and arranged for the 

 question of beauty or ugliness to become anything but a matter of 

 taste. J- B. C. 



LETTERS RECEIVED AND SHORT ANSWERS. 



J. S. T. W. I do not know of any quite recent one ; but the 

 " CyclopSbdia of tho Natural Sciences," published by Richard 

 Griffin & Co., of Glasgow and London, is very good. — Da. Lewins. 



