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NATURE 



{May 30, 1878 



plainly ; and not only may stereographs be combined by the 

 eyes, more readily and with less fatigue than when using an 

 instrument, but they may as readily be inverted (the near objects 

 appearing distant, and vice versd, as if falsely mounted) by 

 applying each eye to the picture in front of the other, in fact, 

 squinting at it. Thus, pictures of any size can be properly 

 combined by reversing the pictures and crossing the eyes, and 

 the width of the pictures is not limited to the distance between 

 the eyes as in the ordinary way. 



An important use of stereoscopic vision is to throw one eye out 

 of use when doing delicate measurement, &c., by directing it to 

 some other and darker object, instead of shutting it ; this is less 

 fatigue, and the attention may be willed on to the eye required, 

 so that the image of the other is not noticed, especially if the 

 eyes be changed occasionally. 



How far the fact of the eyes changing guard naturally by 

 alternations, may suggest that all duplicated organs of the body 

 have alternate periods of rest, I must leave physiologists to 

 investigate. W. M. Flinders Petrie 



Bromley, Kent 



Inside Out 



It appears in Nature, vol. xviii. p. 105, that "if a fourth 

 dimension were added to space, a closed material surface (or 

 shell) could be turned inside out by simple flexure." This im- 

 plies that flexure is necessary. But without displacing a point 

 or a line in the surface we may consistently suppose a rotation 

 of the normals at each point of it through two right angles in 

 a plane polar to the tangent plane. That seems to do the 

 business, C. J. Monro 



May 28 



Physical Science for Artists 



Mr. Norman Lockyer, in Nature, vol. xviii., pp. 59, 60, 

 gives some valuable hints to artists, which, if carried out, will 

 go a great way towards preventing our eyes being hurt by the 

 lunar monstrosities we see at the Royal Academy and elsewhere. 



May I be permitted to add a hint which he appears to have 

 overlooked, and that is, that the inside boundary of a crescent 

 moon is an ellipse ; and in this consists the peculiar beauty of a 

 true crescent. The usual Turkish crescent is struck with two 

 circles, and always looks gouty and bad. Of course the rough 

 edge of a gibbous mooii is also an ellipse. 



Scientific Club, 7, Savile Row, W., Robert J, Lecky 

 May 25 



Dr. P, P. Carpenter's Collection 

 May I ask you to correct an error in the "Notes" of your 

 number for April 25th, relating to the collection of the late Dr. 

 P, P, Carpenter, This collection was permanently placed by 

 him in the museum of this university ; and, mounted under his 

 direction on glass tablets, it now occupies a separate fire-proof 

 room erected for it by the university, and constitutes one of the 

 principal scientific treasures of this university and of Canada, 

 Your correspondent was probably misled by the fact that one of 

 the best duplicate sets was reserved by Dr, Carpenter for his 

 own use in his private residence. This has not been pubUcly 

 offered for sale, but I beheve has been privately offered to 

 certain persons and institutions considered likely to value it, 

 McGill College, Montreal, May 10 J. W, Dawson 



Menziesia Caerulea 



In confirmation of the recent occurrence of the above plant on 

 the Sow of Athol, I may say that it was gathered by Miss 

 Crawford in 1877, ^o^n vs'hom I received a specimen. Like the 

 cotoneaster on the Orme, which has also been reported extinct, 

 careful and prolonged search has generally been rewarded by 

 finding specimens, although the cotoneaster is now very rare. I 

 might take this opportunity of saying that the rare spider orchis, 

 Ophrys aranifera, which the Rev. M. J, Berkeley has gathered 

 at. Southorpe, in Northants, has been destroyed there by the 

 planting of larch, I made a most careful search not only at 

 Southorpe but on the Barnack hills last week, but without seeing 

 a trace of the orchis, although Anemone Pulsatilla and Aceras 

 antkrepophora are still abundant on the unplanted quarries, 



Northampton Natural History Society G, C Druce 



Landrails 



It would prove very interesting to know whether landrails are 

 as plentiful in other parts of the country this season as they are 

 in the neighbourhood of Sheffield. They have not visited us in 

 any numbers since the spring and summer of 1875 ; in 1876 and 

 1877 scarcely one was heard ; while at the present time we hear 

 their well-known calls in almost every meadow. I know of no 

 migratory British bird in whose case this peculiar irregularity of 

 appearance occurs in such high degree as in the landrail. 



If the advice of one interested in the subject may be humbly 

 offered, I would recommend ornithologists to pay strict attention 

 to this matter, this season, with a view of elucidating this peculiar 

 trait in the life-history of this singular bird ; for the cause of this 

 irregular appearance has, for thought I know to the contrary, yet 

 to be learned, ' Charles Dixon 



Heeley, near Sheffield, May 20' 



Hereditary Transmission 



The letter of Mr. Watt reminds me of a similar instance of 

 " Hereditary Transmission " mentioned in the ninth edition of 

 the "Encyclopaedia Britannica." 



It is there stated that " George Bernhard Bilfinger was born 

 on January 23, 1693, at Cannstadt, in Wiirtemberg. His 

 father was a Lutheran minister. By a singularity of constitu- 

 tion, hereditary in his family, Bilfinger came into the world 

 with twelve fingers and as many toes." 



After being a Professor of Logic at St. Petersburg University 

 Bilfinger became one of the "best and most enlightened 

 ministers " of slate that Wiirtemberg had yet produced. 



Burngreave Road, Sheffield, George S. Watson 



May 25 



THE PHONOGRAPH AND ITS FUTURE 



WHAT a surprise is in store for the children next 

 Christmas if Mr. Edison's expectations are 

 realised. Dolls that can say "papa" and "mamma," will 

 be quite at a discount and will bear much the same relation 

 to the doll of the future that the anthropoid ape does to 

 the man of to-day, and the time will probably have come 

 for some Darwinian toy-maker to write the history of doll 

 development, if, indeed, he does not extend his researches 

 to the whole world of toys. We are promised dolls that 

 can speak, sing, cry, laugh ; musical-boxes that will grind 

 out the voice and words of the human singer ; locomotives 

 and every other species of "animal and mechanical 

 toy," that will give out their natural and characteristic 

 sounds. 



But these are only some of the trifles to which Mr. 

 Edison, in an interesting article in the current North 

 Ainericatt Review, tells us his miraculous invention will 

 certainly or probably be put in the near future. And, 

 indeed, a very little consideration will show that there is 

 no end to the uses to which the principle of the phono- 

 graph may be applied; that it may be the means of 

 actually realising some of the wildest dreams and specu- 

 lations of the "frenzied" poet and preacher, and 

 creating a revolution in human intercourse only to be 

 paralleled by the invention of printing, or even of speech 

 itself. Indeed, at first sight it may seem a step back- 

 wards, as it is likely to lead to the abolition, to some 

 extent, of writing and printing, and the substitution of 

 the human voice as the main means of intercourse at a 

 distance. Talk of the solidification of the gases ! Why 

 we have here the solidification of something infinitely 

 more impalpable — human words and human thought. 

 We referred above to the musical-box of the future, and 

 this suggests the phonographic barrel-organ, which will 

 doubtless by and by take the place of that instrument 

 of torture which makes the lives of delicate-eared artists 

 and litterateurs miserable. Instead of having our musical 

 sensibilities harrowed by a murdered reproduction of our 

 favourite operatic air, or our political sympathies shocked 



