582 



NATURE 



\_April 24, 1879 



over the States in early days, but has since been supplanted, 

 as in England, by the brown rat (M. decumanus). Forty years 

 ago the black rat was the only rat in South-west Ohio. About \ 

 tWrty years ago the brown rat drove him out. Some years 

 later the same occurred in Illinois. I have been informed by one \ 

 of my students living in Minnesota, that neither rat is known in , 

 and about the town of St. Cloud in that state, only one having , 

 ever been seen there, and that was killed on landing from a , 

 steamer. I have seen it stated that the black rat is still to \ 

 be found in some localities in England, among them the White- 

 chapel Docks. E. W. Claypole 

 Antioch College, Ohio, April 7 



Did Flowers Exist during theXarboniferous Epoch ? 



I CANNOT accept Mr. McLachlan's reference of the interest- 

 ing Breyeria borinensis to the Ephemeridte, even though he has 

 "examined the fossil," and "has no doubt" about it. The 

 photograph which I possess is so beautifully sharp that it brings 

 out the minutest details, and a careful examination and com- 

 parison of it with specimens and drawings leads me to the con- 

 clusion, that in the general character of the wing-neuration it 

 is strictly lepidopterous and of the Bombycine type, having the 

 costal, subcostal, and median nervures, w ith their branches and 

 bifmcations, arranged precisely as in that group, but differing in 

 the much greater length of the wing and the increased number 

 of the branches of the subcostal vein — seven instead of four. In 

 some of the Chalcosiidse, however, there are often six branches 

 to this vein, but crowded together and sometimes anastomosing, 

 owing to the much shorter apical portion of the wing. In this 

 family also we often have an intermediate falje vein, which is 

 distinctly visible in the fossil. Until, therefore, I am referred 

 to some group of insects with which it more nearly agrees, I 

 must believe it to be an ancestral moth, even though, according 

 to Prof. Haeckel and Mr. Scudder, moths ought not to have 

 existed in the carboniferous epoch. 



After a careful comparison of the photograph with specimens 

 and figures of Ephemeridse, I can see no resemblance whatever to 

 the neuration of the family with which Mr. McLachlan so con- 

 fidently associates it ; while the " dense transverse reticulation " 

 to which he refers seems to me to be merely due to crumpling of 

 the membrane, and certainly bears no close resemblance to the 

 strong reticulation of the veining of the Ephemeridse, and it is, 

 moreover, only visible at all at the base of the wing. The 

 general form of the wing and arrangement of the veins are, 

 however, so different, as, to me, to be conclusive against this 

 view. Alfred R. Wallace 



Blue Flame from Common Salt 



At the present time any spectro?copic observations of coloured 

 flames are peculiarly interesting, and I am glad to see the origin 

 of the blue or violet flame produced by common salt and other 

 chlorides again discussed in your pages. 



In the letter of Mr. Percy Smith (Nature, vol. xix. p. 483), 

 he considers the only feasible explanation to be "that it is due 

 simply to hydrochloric acid," but he gives no proof, and admits 

 that a sptrk between carbon points in a bottle of this gas does 

 not give the violet bands. In a short paper on the subject in 

 the Philosophical Magazine of December, 1862, I considered 

 " this supposition is negatived by the fact that anhydrous chlo- 

 ride of copper emits the.-e rays equally whether it be placed in 

 a flame of hydrogen or of pure bisulphide of carbon." Neither 

 does this characteristic flame seem due to any carbon compound, 

 inasmuch as several chlorides will give it in a hydrogen flame. 

 I also found that "a stream of chlorine or hydrochloric acid 

 passed into a flame never gives the violet hght, nor does Dutch 

 liquid, muriatic ether, or chloroform mixed with alcohol and 

 burnt in a spirit lamp," though chloride of platinum or gold 

 give a flash of it at that temperature. 



W^ould Mr. Smith favoiu: us with any details of his experi- 

 ments which may support his conclusion? 



17, Pembridge Square, April 10 J. H. Gladstone 



to be a diamond, and which was indeed admitted to be a Cape 

 diamond. 



Judgment was given for the plaintiff, because several diamond 

 dealers gave evidence which, the judge stated, clearly showed 

 that what were described as ' ' Cape diamonds " were not at all 

 to be regarded as ordinary diamonds, and the receipt showed that 

 the ring was sold as a diamond ring. The "several diamond 

 dealers " stated that so-called Cape diamonds were comparatively 

 valueless and lacked the essential qualities of the Brazilian stones, 

 viz., lustre, hardness, and colour. 



Now all this is beside the question, which was not as to the 

 value of Cape diamonds, nor yet what they lacked of the qualities 

 of the Brazilian stone, but simply whether this stone was a 

 diamond or not, not even \\ hether it was or was not an ordinary 

 diamond, and I am surprised that any judge could be thus led 

 away from the legal point. 



I see that notice of appeal has been given, and it is to be 

 hoped for the credit of elementary science that the court above 

 will require some scientific evidence, such as specific gravity or 

 chemical composition, about Cape diamonds. If, for instance, 

 it can be shown that they are a form of carbon, the point is 

 settled. 



It would be just as absurd for a person to object to Derby 

 coal as not coal because it lacked the good qualities of Wallsend. 

 The ring was sold as a diamond ring ; the question is : Is the 

 stone a diamond ? 



I have no personal interest whatever in the matter. I know 

 nothing of the case except as it appears in the report. I possess 

 no diamonds, not even a " Cape " ; but I am interested in seeing 

 justice administered with some regard to the scientific knowledge 

 of the day. B. G. Jenkins 



April 14 



Cape Diamonds 



At the Croydon County Court a lady sought to recover 

 36/. 15J. paid for a ring, the stone in which had been represented 



Sense of Temperature 



Your correspondent J. T. B. asks f',r further instances of the 

 cultivation of the sense of temperature. None can be more 

 striking than that of the caste of egg-hatchers in Egypt, who 

 determine the temperature in their ovens entirely without the aid 

 of instruments, and maintain it at 100° to 103° Fahr. during the 

 requisite three weeks. How successful they are is shown by 

 the official return for 1831, given by Lane ("Modern Egyptians," 

 London, 1842, vol. 2, p. 5, et seq.) from whom I take these 

 particulars. Out of a total of 26,204,500 eggs artificially incu- 

 bated, 17,418,973 were successfully hatched. 



April 19 Alfred H. Huth 



Tides at Chepstow 



The highest tides in the Wye and in the Severn for the pre- 

 sent year were on Tuesday, April 8. On that day, up the Wye, 

 at Llandogo, the tidal rise was 13 feet ; at Tintern Abbey, 21 

 feet 5 inches ; at Chepstow Railway Bridge, 44 feet. Up the 

 Severn, at Newnham, the tidal rise was 20 feet j at Portskewitt, 

 46 feet 6 inches ; at Cardiff, 44 feet ; at Clevedon Pier, 52 feet. 



Reference to Coxe's "Historical Tour in Monmouthshire," 

 4to Edition, 1801, p. 358, containing his own soundings at high 

 tide, on September 4, proves that there has been no perceptible 

 change in the depth of the Wye at high tide this century. 



The Severn has been confined within narrower limits by the 

 South Wales Railway embankment, on the Monirouthshire side, 

 since 1850, and by Lord Fitzhardinge's breast-works on' the 

 Gloucestershire side, from about same date, but the height of the 

 tide and the depth of the river have not been sensibly affected 

 by these slight alterations. One fact further may be worth men- 

 tion, however : a gun-boat or armed sloop, commanded by 

 Capt. White, came up the "Pill," below St. Pierre, in 

 1827, on a surveying expedition, remained at anchor some 

 days, and re-entered the Severn without difficulty, piloted 

 by W. Wheeler, a thing that would now be impossible on 

 account of the embankments. The Pill is a mere creek— the 

 "anchorage," dry ground. John Yeats 



OUR ASTRONOMICAL COLUMN 

 Brorsen's Comet.— The following ephemeris of this 

 comet for May is deduced from Dr. Schulze's elements, 

 with the time of perihelion passage corrected so as to 

 accord better with the observ'ations in March at Florence 

 and Kremsmunster. The heliocentric co-ordinates, re- 

 ferred to apparent equinox of May i, for combination 



