464 



NA TURE 



[March 15, 1906 



•quite apart from the earth V rotation the force of gravity 

 impelling a body to the ground is not correctly measured 

 In tin' rate of change of momentum relative to the earth. 

 Though the neglect of the mass of the body itself, compared 

 villi that of the earth, may not' lead to serious contradic- 

 tions in this particular instance, the definition is wrong in 

 prim iple unless absolute momentum be meant, or unless 

 it be specified that the momentum has to be taken relative 

 to some body unacted on by any forces. 



For our definition of force we shall have to return to 

 Newton, and I may have to trouble you with a further 

 communication to justify my belief that though modern 

 criticism has been able to point out the weak spots of the 

 Newtonian system, it has failed to substitute any more 

 sei ure or more logical basis for our foundation of 

 ' banics. Arthur Schuster. 



The Diffusion of Solids. 



I\ view of the interest attaching to the vaporisation and 

 diffusion of solids, the following observations may be 

 worthy of record. 



1 to the inside of the case of a silver watch between fortj 

 and fifty years old, and opposite the steel pin of the kej 

 hole, .1 diffused, dark patch, larger than the kej hole 

 itself, was noticed. When a drop of strong hydrochloric 

 acid was placed on the spot, hubbies of gas were evolved, 

 and thi colour gradually became lighter, though alter ten 

 minutes, when action had apparently ceased, the patch was 

 still plainly marked. On adding' a drop of potassium 

 ferrocyanide solution the blue precipitate due to iron was 

 formed. Similar results have been obtained with other old 

 watches. Since it was shown that the iron was not in 

 contact with the silver, the facts indicate that the iron, or 

 possibly some compounds of iron contained in it, vaporises, 

 dissolves in the silver, and penetrates for some distance 

 into the latter by diffusion. 



Prof. F. D. Brown has observed an effect of similar 

 nature. On a porcelain writing tablet were notes written 

 in Macklead perhaps forty years ago. While recent writing 

 is e.isih lemoved, these- marks can no longer be defaced 

 in any way by washing or mere surface scratching, showing 

 that the carbon has penetrated into the porcelain no in- 

 considerable distance. That this should have taken place 

 in the case of two such refractory solids as carbon and 

 porcelain is all the more remarkable. 



John H. How i i i 



Grammar School, Auckland, N.Z., February 4. 



Earth Tremors in India. 



In connection with the short description of the Kangra 

 earthquake, and the reference to the still greater earth- 

 quake of 1897, contained in Nature of March 1, p. 418, 

 it may be of interest to note that, at a distance of about 

 twelve miles from the point that was supposed to be the 

 centre of greatest disturbance in the latter earthquake, 

 tremors were still appreciable, at frequent intervals, in the 

 early part of 1004. 



While we were sitting on the verandah of the Govern- 

 ment bungalow at Rongmudu, in the Garo Hills, near the 

 poinl ai which the river Somersary changes the direction 

 >l Hs How from east to south, in the early afternoon of 

 February to, 1904, my travelling companion, Mr. A. B. 

 Nowell, of Dwarra, Svlhet, directed my attention to a 

 booming sound like the beating of distant gongs, and al the 

 same time pointed to a glass of water standing on the 

 table in front of us, in which the water was distinctly 

 agitated. The tremor lasted for only ten or fifteen seconds. 



Mr. Nowell, who had spent some months of each year 

 in that neighbourhood for several years in succession, in- 

 formed me that tremors occurred' at frequent intervals 

 every clay when he first came there, but were getting fainter 

 and less frequent as time went on. Later in the same 

 ■day he directed my attention to another tremor, but as we 

 were then walking in the jungle 1 failed to appreciate it. 

 On the following day we travelled many miles southwards, 

 "i' awa\ from the centre of disturbance, so that I had no 

 luri her opportunity of observing these phenomena. 



W. Galloway. 



NO. 1898, VOL. 73] 



Peculiar Ice Formation. 



I should like to direct attention to a peculiar ice form- 

 ation which 1 have noticed during the last week on the 

 moorland area at this place, and I should be glad to know 

 if this phenomenon has been observed elsewhere. 



The moorland here is of considerable extent, and at a 

 height of 1000 feet above the sea level. The rocks on the 

 upper surface are of a brittle shale with outcropping sand- 



s , and on the lower slopes beds of clay and gravel. On 



March 2 1 noticed the surface of the ground for distances 

 of a hundred yards or more raised to a height of from 

 1 hi 2 inches, and supported by ice pillars, which had 

 evidently grown by addition of water from below the 

 surface. The sensation of walking on these patches was 

 somewhat analogous to that observed when walking upon a 

 good pile carpet. The late snows had all melted, but the 

 surf. ire contained much moisture, and there had been a 

 certain amount of frost tin previous night. The time was 

 9.30 a.m., and as I stood there these ice pillars crackled 

 and fell in such order as to give the surface a honev- 

 combed appearani e. 



I found on examination all the talus slopes in the 

 gullies of the moorland to be covered with the same ice 

 structure. These ice pillars were not very evident until 

 some of the earth had been cleared away, as a thin laver 

 of earth was held up in a very uniform manner on the top 

 "I 1 In 111. I found them perpendicular to the surface, both 

 on the pathway and upon the inclined surfaces in the 

 gullies. Several hours afterwards, when the heat of the 

 sun's rays had melted the ice pillars, the whole surface pre- 

 sented a honeycombed appearance. I only noticed this to 

 have taken place in those areas void of any vegetation what- 

 ever, and where the heat would be quickly radiated into 

 the atmosphere. The whole of these areas is now broken 

 up into a very fine titrated soil ; if this tendency to super- 

 ficial vertical ice thrust is at all general, it appears to nie 

 in be a great factor in the disintegration of surface soils. 



J imes Foulds. 



Darwen, Lancashire, March 5. 



Cooperation between Scientific Libraries. 



In connection with the discussion raised by the note on 

 Dr. Muir's paper (p. 372) and Dr. Bather's letter, it may 

 he of interest to note that the Royal Irish Academy, some 

 five years ago, prepared a classified card-catalogue of the 

 scientific serials accessible in various libraries in Dublin, 

 and it is proposed to keep this up to date through the co- 

 operation of the various librarians. This catalogue is 

 always ready for reference by any member or visitor in 

 the academy's reading-room; and it has been of late years 

 tin custom for the library committees of various Dublin 

 institutions to inquire, when a new periodical is proposed, 

 as to its possible previous inclusion in one of the other 

 libraries. Grenville A. J. Cole. 



.March 10. 



Sounding Stones. 



With regard to Mr. Tingle's letter in Nature of 

 January 4 (p. 222) on sounding stones, it may interest you 

 to know that I have just seen at Pagan, the former capital 

 of Burma, now in ruins, a large log of fossil (or rather 

 silicified) wood, used as a gong. It emits a clear ringing 

 note when struck, and is used, like all pagoda bells or 

 gongs, to direct the attention of the guardian spirits to 

 the offering about to be presented by the pious Buddhist. 

 O. F\ Wheeler Cuffe. 



Meiktila I'pper Burma, February 11. 



An Inquiry for Books. 



Can any reader of Nature direct me in English books 

 on the history of Arabic literature, historj oi Arabic educa- 

 tion, and general sanitation? G. Hammam. 



Oriental College, Zahleh, Beirut, Syria, February 24. 



