May 22, 1890] 



NATURE 



oscillating layer at the surface of the sensitive plate. Being 

 anxious to keep the alcohol in the cell (which in this instance 

 was closed by a ground glass cap), I sealed the cell into a glass 

 tube through the extremities of which the wires of the cell passed. 

 The effect of the disturbance thus resulting was that no amount 

 of tapping the support of the cell would change it from the 

 sensitive to the insensitive state, although before being thus 

 treated it was sensitive to the most minute disturbance. I sus- 

 pected, however, that after some hours the liquid and the plate 

 would again enter into the peculiar relation on which the im- 

 pulsion results depend, and so it turned out — after three hours 

 the cell could be rendered insensitive by taps and sensitive by 

 the inductive effect of a Voss machine. The platinum wires were 

 soldered to the plates. I see that the distances at which I found 

 the Hertz oscillator effective in influencing the cells were greater 

 than those above stated ; but I have not been able to renew work 

 with the oscillator, which belongs to Mr. Gregory, who removed 

 it for exhibition at the Royal Society's meeting. 

 May 16. 



Bison not Aurochs. 

 I AM glad that Mr. Lydekker accedes (NATURE, May 15, 

 p. 53) to the correction of which I had pointed out the need. 

 But the " vulgar error " — if the Editor will allow me to use a 

 phrase made classical nearly 250 years ago by Sir Thomas 

 Browne — is of more ancient date than my friend seems to 

 suppose ; and Dr. Gadow has kindly referred me to Prof. 

 Wrzesniowski's " Studien zur Geschichte des polnischen Tur," 

 published in May 1878 {Zeitschr. fiir wissenscl.afil. Zoologie, 

 xxx. pp. 493-555). Therein will be seen reduced copies of the 

 engravings in an edition of Herberstein's " Rerum Moscovitic- 

 arum Commentarii " (BasilejE : 1 571), giving a figure of each of 

 the animals. The first is inscribed 



VRVS SVM, POLONIS TVR, GERMANIS AVROX : 

 IGNARI BISO.NTIS NOMEN DEDERANT. 



Over the second may be read 



BISONS SVM, POLONIS SVBER, GERMANIS BI- 

 SONT : IGNARI VRI NOMEN DEDERANT. 

 This paper is well worth reading from the amount of curious in- 

 formation to be found in it. I have been able to consult only 

 one copy of this work, of an earlier edition indeed, for it was 

 published at Antwerp in 1557 ; but it does not contain these 

 figures, though the passages quoted by the Polish Professor of 

 course occur {ff. W] verso et seqq.). The figures are not remark- 

 able for beauty, and if anyone were to call them caricatures I 

 should hardly complain ; but they are certainly of interest, and 

 that of the Urus, which I think I have seen copied elsewhere, 

 is perhaps the only approach to an original representation extant. 

 If so it deserves to be better known. Allow me to remark that 

 this is not the first time that I have noticed this error. I did so 

 many years ago in a little pamphlet " On the Zoology of Ancient 

 Europe " (p. 14), published by Messrs. Macmillan in 1862 ; and 

 I may add that any visitor to the Museum of Zoology of this 

 University may see therein a skeleton of the Aurochs and of the 

 Bison, as well as of the American "Buffalo" — all standing side 

 by side. Alfred Newton. 



Magdalene College, Cambridge, May 18. 



Sudden Rises of Temperature. 



In Nature, vol. xli. p. 550, it is stated that sudden rises of 

 temperature of large amount in Great Britain " are more frequent 

 and more extensive in amount than sudden falls — the reverse to 

 what obtains in India." There appears to be a somewhat similar 

 condition of affairs in North America. Extremely sudden and 

 large rises of temperature attend the warm Chinook winds, as 

 they are called, which occur over the western part of the con- 

 tinent, but are unknown further east. Equally pronounced are 

 the sudden falls of temperature in the eastern half of the country 

 popularly termed "cold waves." M. A. Veeder. 



Lyons, N.V., May 7. 



Coral Reefs, Fossil and Recent. 



In Dr. von Lendenfeld's communication to Nature of May 8 

 (p. 30), occurs the following : — 



"Dr. Murray goes on to say . . . and an isolated atoll rising 

 precipitously, perhaps 10,000 feet from the sea-bottom, will be 



NO. 1073, VOL. 42] 



formed." And again — "and far less will it enable an atoll 

 rising 10,000 feet or more from the bottom of the sea . . . " 



I cannot think that the author quoted has committed himself 

 to any such figures as these, but if either he or Dr. von Lenden- 

 feld can tell me where to find such a formation in existing seas, 

 I shall be obliged ; as I have sought in vain for instances yet 

 known of any slopes that could be called "steep" descending to 

 more than 4000 feet or so, vi\{\\c precipitous slopes are unknown 

 to nie beyond 1200 feet ; and these are, so far as I know, very 

 exceptional. 



While I am writing on this subject, I should be glad if anyone 

 would explain how, on the assumption that atolls are formed 

 during subsidence, it comes about that, while the outer slopes 

 descend to great depths, the depth of the largest lagoons inclosed 

 is generally confined to about 45 fathoms, and in one or two 

 cases to 60 fathoms, but is never more. Why should not the 

 lagoon of an atoU twenty or thirty miles in diameter, which 

 rises steeply from depths of 200 or 300 fathoms or more, have a 

 depth of at any rate 100 fathoms, allowing for the most extrava- 

 gant amount of silt from the debris of the rim. 



W. J. L. Wharton. 



Doppler's Principle. 



A complete solution of the questions about which your 

 correspondents are puzzling themselves has been before the 

 public for some ten years in several successive editions of my 

 "Deschanel." It occurs in the last paragraph of the chapter 

 entitled " Numerical Evaluation of Sound," and is as follows : - 



" Let the source make n vibrations per second. Let the 

 observer move towards the source with velocity a. Let the 

 source move away from the observer with velocity a' . Let the 

 medium move from the observer towards the source with 

 velocity m, and let the velocity of sound in the medium be v. 



"Then the velocity of the observer relative to the medium is 

 a - m towards the source, and the velocity of the source relative 

 to the medium h a' - m away from the observer. The velocity 

 of the sound relative to the source will be different in 

 different directions, its greatest amount being v + a' - m to- 

 wards the observer, and its least being v-a + m away from the 

 observer. The length of a wave will vary with direction, being 



- of the velocity of the sound relative to the source. The 

 n 



length of those waves which meet the observer will be , 



and the velocity of these waves relative to the observer will be 



v-Va-vi; hence the number of waves that meet him in a second 



•11 1- v-\-a - m „ 

 will be ; n. 



The three quantities a, a', in may of course be either positive 

 or negative. J. D. Everett. 



5 Princess Gardens, Belfast, May 1 7. 



THE SHAPES OF LEAVES AND 

 COTYLEDONS} 



ATTEMPTS to explain the forms, colours, and other 

 characteristics of animals and plants, though not 

 new, were until recent years far from successful. Our 

 Teutonic forefathers had a pretty story which explained 

 certain characteristics of several common plants. 



Balder, the God of Mirth and Merriment, was, charac- 

 teristically enough, regarded as deficient in the possession 

 of immortality. The other divinities, fearing to lose him, 

 petitioned Thor to make him immortal, and the prayer 

 was granted on condition that every animal and plant 

 would swear not to injure him. To secure this object, 

 Nanna, Balder's wife, descended upon the earth. Loki, 

 the God of Envy, attended her disguised as a crow (crows 

 at that time were white), and settled on a little blue 

 flower, hoping to cover it up so that she might overlook it. 

 The flower, however, cried ort " Forget-me-not, forget- 

 me-not" (and has ever since been known under that name). 

 Loki then flew up into an oak and sat on a mistletoe. 

 Here he was more successful. Nanna carried off the 



« Lecture delivered at the Royal Institution on April 25, by Sir John 

 Lubbock, Bart., M. P., O.C.L., K.R.S., &c. 



