Nov. 5, 1885] 



NATURE 



seven o'clock, stood at 30" immediately after totality ; the keen 

 breeze which was blowing before the sun was shadowed died 

 completely away at the time of totality." I inclose a photo- 

 graph whicli clearly shows the protuberances noticed by all the 

 observers. Killingworth Hedges 



Westminster, October 30 



An Earthquake Invention 



The object I had in view in my former commimication to 

 Nature (vol. xx.tii. p. 213) on this subject, has been attained, 

 as the following quotations from Prof. Milne's letter in Nature 

 (p. 573) show : "I have no desire to claim the authorship of the 

 aseismatic joint ;" and again, '*! am as yet in the dark as to 

 who w.as the first inventor of the aseismatic joint." 



Well, I can enlighten him, and I claim the invention for 

 Mr. David Stevenson, whose paper describing it was read before 

 the Royal Scottish .Society of Arts in 186S, and published in 

 their Transactiotn ; whose firm designed, superintended the con- 

 struction of, tested and sent out to Japan seven lighthouse 

 apparatus, carried on tables 8 feet in diameter, fitted with this 

 contrivance. Further Messrs. Stevenson designed two light- 

 house biiildiit^s, iron towers 29 feet in diameter at the base and 

 46 feet in height, with an aseismatic joint fl////t-/;-/'(2j£-, which were 

 constructed and ended in the work-yard of the contractors in 

 Edinburgh, .and finally, in 1869, shipped to Japan, but un- 

 fortunately they never reached their destination, as the vessel 

 went down on tlie voyage out. 



There are three points in Prof. Milne's letter on which I wish 

 to make a few remarks. The first is to give the explanation 

 Prof. Milne asks as to the part the late Mr. Mallet took in the 

 invention of the aseismatic joint which I may observe Mr. 

 Mallet never claimed for himself. Mr. Stevenson consulted 

 with Mr. Mallet as to what was the exact micaniq7ic of an earth- 

 quake shock, and how he thought it would affect the delicate 

 apparatus usually placed in a lighthouse. This information 

 Mr. Mallet furnished, but so far from suggesting a Ijall and 

 plate joint, he expressed a fear that the superstructure, if placed 

 on balls as proposed by Mr. Stevenson, would be thrown down, and 

 in a letter dated March 14, 1868, acknowledging a copy of the 

 Scotsman newspaper, containing a notice of Mr. Stevenson's 

 paper, he says that if the balls and plates proposed are confined 

 to the apparatus in the light-room, he "would augur much 

 more favourably of the result being satisfactory," but that his 

 "own notion for Japan or other shaky places would be to make 

 all the towers rather of timber or of boiler plate work." This, 

 I think, should put Prof. Milne's mind at rest on this point. 



The second point is with reference to ball and plate seismo- 

 graphs. I never described a seismograph, but my brother did, 

 in 1883, in Nature, vol. xxviii. p. 117, though, so far from 

 claiming the idea as original, he says : " The idea of the instru- 

 ment I propose was suggested to me by the aseismatic arrange- 

 ijient designed by my father, Mr. David Stevenson, for averting 

 damage to buildings and lighthouse apparatus in countries 

 subject to earthquakes." 



I entirely agree with Prof. Milne that the joint employed in 

 ball and plate seismographs, lamp tables in Japanese lighthouses, 

 model houses, and the Professor's own dwelling-house, all " in- 

 volve the same principles, and they only differ in their dimen- 

 sions," and my point is that Mr. David Stevenson was not 

 only the original inventor of this contrivance, but, what is of 

 far more importance, suggested and carried into practice the only 

 known method of mitigating the effects of earthquake- shocks on 

 buildings, and the astatic house of which Prof. Milne reported 

 such good results to the British Association of 18S5, which is 

 described in Nature, vol. xxxii. p. 527, as being "rested at 

 each of its piers upon a handful of cast-iron shot each a quarter 

 of an inch in diameter " placed "between flat iron plates," is 

 obviously merely a modification of the same principle. 



The third point is as to the success of the .aseismatic joint. It 

 does seem a little curious that Prof Milne, in the Transactions, 

 lliitish Association of 18S4, when he appeared to me and to 

 others to claim the invention for himself, thought it perfection, 

 Ih jugh now he appears to have changed his mind. I do not 

 think, however, it affects the question .at issue, whether the 

 a eismatic joint is a success or not ; but that it is a success will 

 be seen from Prof. Milne's own reports in the Transactions of 

 the British Association, and from the following information 

 which was supplied by Mr. Simpkin in 1884, who had just re- 

 turned from Japan, where he was eng.aged in the lighthouse 



service. At Isuragisaki and Kashmasaki lighthouses the aseis- 

 matic tables were firmly strutted with timber to prevent any 

 motion, as inconvenience was felt from the oscillations of the 

 table when w inding up the machine, the steadying screws sent 

 out with the apparatus for the purpose of temporarily doing so 

 h.aving for some reason not been put in at these stations. These 

 tw o are the only lighthouses at which any damage has been done 

 by earthquake, while those stations at which the tables are in 

 operation have never suffered at all, although they have been 

 repeatedly subjected to shocks ; but for full particulars as to 

 this see Nature, vol. xxx. p. 193, and vol. x.xxii. p. 316. 



Prof. Milne excuses himself on the ground that he was 10,000 

 miles away from a library and never saw Mr. Stevenson's paper, 

 but surely Nature finds its way out to Japan, and this subject 

 has been referred to in your columns fiequently ; it was also 

 discussed in 1876 before the Institution of Civil Engineers, and 

 an account of it was published in their Transactions : but, after 

 all, the apparatus was actually at work in Japan where he was 

 Imng. D. A. Stevenson 



84, George Street, Edinburgh, October 19 



The Mithtin 



I was glad to see in Nature of July 16 (p. 243) that Mr. 

 W. F. Blanford had drawn attention to the extraordinary mis- 

 take made by Dr. Kuhn in considering the gayal and gaur 

 specifically identical, and their differences as due to domestica- 

 tion. If this latter were true we should see endless intermediate 

 forms instead of two invariably distinct. To those who know 

 them in their habitat the confusion must seem extraordinary, 

 even though both are here called " Mithun." The gayal {B. 

 frontalis, v. gavasus) is known (domestic only) all through these 

 hills, and not in the plains ; is pied black and white, with pink 

 muzzle, white legs, and the tips of the horns point outwards. 

 Tile gaur (B. gatirus, v. cavifrons) is only known wild, in the 

 hills and also plains, never pied, has white legs, and the tips of 

 adult horns invariably point inwards. The gayal domestic, and 

 never known wild ; the gaur wild, and never known domestic ; 

 and they do not cross. I have known both here now many years, 

 and had good opportunities of observing and contrasting them. 

 I have had a fine bull gaur feeding along beside me at twenty 

 yards in short grass for over quarter of an hour, as I sat motion- 

 less in my Rob Roy canoe, an enormous Dontal (tusker) elephant 

 at the same distance off on the opposite bank ; each occa- 

 sionally left off to sniff me, but resumed again, taking me, in 

 brown-grey costume and grey-coloured canoe, for a snag in mid- 

 stream (which stream was deep and stagnant). It is not always 

 easy or possible to point out to such a man as Dr. Kuhn that the 

 study of the "dry bones" of an animal is really but half the 

 battle in comparing it with its allies. The study of specific dis- 

 tinctions should include the whole animal, alive as well as dead. 



But the clearest proof that these two distinct forms are not 

 due to domestication is that, instead of endless intermediate 

 forms, we find absolutely none. S. E. Peal 



Sibsagar, Asam, September 26 



On the Behaviour of Stretched India-rubber when 

 Heated 



I SHOULD like to make the following remarks with reference 

 to the letter of Mr. H. G. Madan which appeared in the last 

 number of Nature : — 



(a) Though the fact that india-rubber becomes kot when 

 stretched might be, and no doubt is to be, partly attributed to 

 molecular friction, we cannot thus account for the cooling which 

 resulted from contraction in the experiments of Joule and Sir 

 William Thomson. 



(/') Te.xt-books as a rule are not, I am afraid, sufficiently ex- 

 plicit as to whether the stretched india-rubber is contracted in 

 vohime when heated, or only in length. Thermodynamic theory 

 does not require, in order that longitudinal pull should produce 

 rise of temperature, that the volume should be diminished when 

 the temperature is raised, and the results of Joule's experiments 

 are in reasonable accord with theory. 



(c) The real state of things seems to be that the effect of 

 heating a stretched piece of india-rubber is to lengthen it if 

 the tension is small, and to shorten it if the tension is large (Hr. 

 Schmulewitsch, Vierteljahrschrift dcr Natitrforsch. Ctsellschaft, 

 Zurich, xi. 202) ; thus, for a certain tension there will be neither 

 elongation nor contraction, and my own experiments on the 



