268 



NATURE 



{July 20, 1 88; 



men and women there is a striking and peculiar physiognomy, 

 which is the same in hundreds of the sculptures ; there are other 

 traits equally persistent, and the ornamentation — of which there 

 i, so much on the figures, tablets, and vases, is unique, and 

 ves a constant relation. The uniform observance of such 

 characteristics in so large a* number of objects, would seem to 

 determine them as "typical," no matter who were the makers of 

 them, or when they were made. 



Dr. Rau believes, he says, that the " carvings" originated in 

 comparatively modern times. I should be pleased to have any 

 evidence either from colonial or other history of West North 

 Carolina, that might throw light upon their production, as I have 

 rent much valuable time in endeavouring to find such evidence. 



Dr. Rau continues: — "They ('the carvings') were made by 

 a few individuals of the Indian, or, perhaps, even of the 

 Caucasian race." But he has already said that they do not 

 "resemlile the well-known specimens of modern Indian art." 

 How, then, does he know that "they were made by a few indi- 

 viduals of the Indian race ? " And I would ask why members 

 either of the Indian or Caucasian races have chosen to make 

 representations of other peoples than themselves, and with other 

 characteristics than their own? Why Indians, who are notori- 

 ously prone to war, should have, in their representations, so 

 carefully absented all of its indications, and emphasised the 

 pleasures and avocations of peace? And again, why — if the 

 "carvings" were made by a Caucasian, the maker has so 

 studiou-iy refrained from placing any letter, sign, or symbol, 

 significant of his race or religion, on any of the 2000 objects ? 



" The rude attempts at imitating animals of the Old World," 

 proceeds Dr. Rau, "are conclusive evidence that the makers 

 either had seen such animals, or knew at least that they 

 existed." Not necessarily — for they may "be rude attempts at 

 imitating animals" of the New World. The mounds of the 

 United States indicate that an intercourse existed between dif- 

 ferent tribes and peoples remotely separated ; and, why could 

 not peoples, while trafficking to, or emigrating from extreme 

 points, carry with them impressions sufficiently forcible for 

 " rude attempts at imitating, and the peccary, the tapir, and 

 the llama, perhaps have been the models for the production of 

 some of these apparently " Old World animals?" 



Dr. Rau objects to "potstone"as a material for endurance, 

 whereas it is found in the mounds in better state of preservation 

 than clay pottery. He has not been made aware, perhaps, that 

 the element of fire has caused much more damage to these 

 carvings than "exposure." He may remember that the 

 "carvings" were coated over with a greasy-looking soot — for 

 their better protection, possibly, as the coating was made to 

 penetrate well into the surface of the stone. Nevertheless, many 

 of them are in a very bad condition. But if there were not 

 well-preserved antiquities — and imitations also — in an admirable 

 state of decrepitude, even in the museums, I conceive that there 

 are more important matters to be considered in connection with 

 these carvings than the material of which they were made. 



In conclusion, it is perhaps to be regretted tbat Dr. Ran has 

 not in his communication suggested any satisfactory explanation 

 of the "curious stone carvings from the neighbourhood of 

 Mount Pisgah, and that he leaves the subject with such dubious 

 language as ' modern intrusion.' " Mann S. Valentine 



iuly 17 



Movable Coils 

 . Obach's letk rmati .n which I am much 



pleased to obtain. 1 rs. Siemens' use of fine alu- 



minium v. ire for a relay, Mr. Yarley stated that it had been tried 

 by his brother or himself for the moving coil of a syphon 

 recorder, but without notable advantage over gold. With such 

 currents as would be available in these two cases, no doubt 

 slight variations in resistance would be of the utmost detriment. 

 With the small but high-tension currents of an induction-coil, 

 the case is materially different : whereas the lightness of the 

 moving oil, as I endeavoured 'o show, enables currents "of 

 moderate intensity " to be app dated. 



The resistance of I metre of copper wire I millim. in diameter 

 is given in Sabine's tables as 106 as compared with silver, and 

 that of aluminium 1*94. I find the the weight of the two to be 

 respectively 27 and 0*99 grammes. This is, of course, when 

 both are silk-covered. The ratio between the densities of pure 

 copper and aluminium is 344. The silk covering lessens 

 the aggregate weight of the copper, and increases that of the 

 aluminium, so that the ratio becomes 2'72. 



It is, however, obvious that, weight for weight, aluminiu 11 

 will carry much more electricity than copper. 



The junctions of gold and aluminium have hitherto given no 

 trouble, nor has the total resistance of the little dynamometer 

 altered ; though it has had a double railway journey, partly in 

 third class, of about 120 miles. W. H. Stone 



14, Dean's Yard, Westminster, S.W., July 15 



The Analysis of the Tuning Fork 

 With reference to the letter of Mr. Stanley in NATURE, vol. 

 xxvi. p. 243, I notice the following sentence: — "If we may 

 apply this principle to stringed instruments, we must look rather 

 to the bridge than the transverse motion of the string, as the 

 communicator of the sonorous vibrations which produces the 

 note." I thought that this was an admitted fact. Upon the 

 shape of the bridge depends the tone of the instrument, as was 

 satisfactorily settled by Stradivari. The bridge is usually made 

 of spotted maple, and its thickness is of the greatest importance, 

 for if it is too thick it will fail to respond to the string vibration. 

 A plain piece of wood as a bridge is absolutely useless, and the 

 tone increases as the proper shape is approximated to. 



Rugby, July 14 George Ravleigh Vicars 



The Chemistry of the Plante and Faure Cells 



I have read with much interest the important researches of 

 Dr. Gladstone and Mr. Tribe into the chemistry of lead 

 secondary batteries, and my own experience has been in general 

 very confirmatory of their conclusions ; but I am in a difficulty 

 concerning one point in their third article, which appeared in 

 vour last issue, and I should be glad to be allowed to ask a 

 question. 



The conclusion that during discharge the reduced spongy lead 

 is changed to sulphate of lead is, no doubt, the natural one, and 

 it appears to be confirmed by the analysis of .Messrs. Gladstone 

 and Tribe ; but then, if this is the sole product, how is the cell 

 able to be recharged ? For I find that if the plates are spread 

 originally with PbS0 4 , instead of with minium, it is scarcely 

 possible to charge the cell. The coating to be oxidised will 

 indeed allow itself to be acted on very slowly, but the coating to 

 be reduced remains perfectly unchanged. This led me to sup- 

 pose that the sulphate formed on discharging a cell was perhaps 

 so intimately mixed with some oxide that the reducing action 

 could as easily go on as at tke first formation "f the cell. But 

 this hypothesis scarcely seems borne out by Messrs. Gladstone 

 and Tribe's results ; for though a-good deal of unaltered peroxide 

 is found after di-charge on the one plate, yet on the other they 

 speak of sulphate as being ultimately the sole -product of the 

 discharge. It may be that they used a large excess ot acid in 

 their cells, but if so, it would be interesting to know whether 

 either of the discharged plates refused to charge up again. 



I doubt very much whether, in the cells of commerce, there is 

 anything like enough acid present to combine with all the lead, 

 and I think that in these a great part of the spongy lead 

 would have to be content to oxidise itself somewhat and so 

 remain ready to be reduced again when the charging current i; 

 applied. I by no means deny that sulphate mixed with other 

 things can be acted on, but I do find- that it is reduced with 

 some difficulty, and when by itself not at all. 



I hope, however, that my question may be the means of 

 eliciting further information from the more extensive experience 

 of Messrs. Gladstone and Tribe. Oliver J. Lodge 



University College, Liverpool, July 14 



A Curious " Halo " 



I take the liberty of communicating an observation made on 

 Saturday evening list between 8 o'clock p.m. and S'lS p.m. of 

 a sort of halo which ap] eared in the east-south-east, just over 

 Killiney Hill. Near the horizon was a bank of heavy, slate- 

 gray clouds coining up from the south, and from behind rose up 

 a principal beam from the Telegraph Hill, Killiney, with two 

 side beams of lesser intensity or. the sides, at angles of about 

 2S°-30° were lesser beams diverging from the common centre. 



All those beams were dark, or appeared so against the sky. 

 I mention the appearance, as the weather since has been singu- 

 larly cold and rainy for the season. J. P. O'Reilly 



Royal College of Science for Ireland, Stephen's Green, 

 Dublin, July 17 



