42 



NATURE 



[May 8, 1879 



Alsace-Lorraine. The exhibition will keep open from July 15 

 to the end of November, but a limit will be imposed on exhi- 

 bitors sending in their applications. 



On April 27 an earthquake was felt at Florence, and also at 

 Bologna. The Florence commotion was very slight, but had 

 been preceded by other movements of a similar nature, which 

 ought not to pass unnoticed, especially in connection with the 

 seismic manifestations felt in Germany, as mentioned in our last 

 impression. 



Mr. Rowland Ward writing to the Standard, states that in 

 making the excavation at Charing Cross for Messrs. Dnimmonds' 

 new bank, the workmen, at depths varying from fifteen to thirty 

 feet, came upon the fossil remains of various extinct animals. 

 They include elephant tusks and molars (probably the mammoth 

 Elephas primigenius), teeth and numerous bones of the gigantic 

 extinct ox (Bos primigenius), a portion of the horn of the great 

 extinct Irish deer (Megaceros hibernicus), along with various 

 other remains of ruminating animals not yet identified. The 

 specimen in this series which has specially attracted notice is the 

 extreme end of a tusk unusually sharp at the point and highly 

 polished, and from a portion of the surface of which a very thin 

 skin of ivory peels off, exposing a strongly and regularly longi- 

 tudinally channelled surface beneath. 



Mr. Watson Lyall's "Sportsman's and Tourist's Guide" 

 improves every year. It has now reached its seventh year, and 

 is evidently a great success. The information as to shootings, 

 rivers, lochs, &c., of Scotland is as full as could be, and is evi- 

 dently kept well up to date. It deserves all the success it has 

 obtained. In this connection we greatly regret to see that the 

 disease which we referred to last year as having broken out 

 among the Solway salmon has reappeared this year, not only in 

 the Sol«ay rivers, but in the Tweed. Mr. Sterling, of the 

 Edinburgh Anatomical Museum, found it to be a branching 

 fungus (Saptolegnia ferax), which, first attacking the scaleless 

 parts, rapidly spreads over the whole fish. The disease has not 

 yet appeared north of the Tweed. Sir Robert Christison re- 

 commends a Royal Commission, and the careful watching of 

 all salmon and trout streams, whether affected or not. 



We are glad to see from its Twenty-first Report that the East 

 Kent Natural History Society is fulfilling its functions, though 

 under many disadvantages. 



We have already referred to the forthcoming annual meeting, 

 at Leicester, of the Midland Union of Natural History Societies. 

 Those interested in the meeting will find further details in our 

 advertisement columns. 



Ik Prof. Jevons's article (vol. xix. p. 588), second column, 

 line 18, for "a seer is equal to about 21 lb. avoirdupois," read 

 "a seer is equal to about 2 lb. avoirdupois." The error is a 

 purely typographical one, and does not affect any other state- 

 ments in the arlicle. Mr. E. H. Tringle asks us to state that in 

 his letter (vol. xx. p. 6), "such distances as six," &c., should 

 be "such heights as six," &c., and "mountain 20,000 feet high 

 (less than 4 mile^)" should be " mountain 10,000 feet high (less 

 than 2 miles)." He thinks it may be worth mentioning that 

 Raoul or Sunday Island, in the Kermadecs, has an elevation of 

 1,627 feet, commanding a sea hjrizon of nearly 50 miles radius. 



The additions to the Zoological Society's Gardens during 

 the past week include a Bonnet Monkey (Macacus radiatus) 

 from India, presented by Mr. E. Brett ; a Pig-tailed Monkey 

 (Afacacus nemestrinus), from Java, presented by Mr. E. M. 

 Cli-sold ; a Black-faced Spider Monkey {Aides aUr) from 

 Eastern Peru, two Passerine Ground Doves (C/iamapelia 

 passerina) from America, presented by Capt. II. King; an 

 Ocelot (felis pardalis) from America, presented by Mr. B. II. 

 Jones ; a Crab- eating Raccoon [Procyon cavcrivorus) from from p. 21. 



South America, presented by Mr. Bridget ; a Long-tailed 

 Marmot (Arctomys caudata) from Bhootan, presented by Capt. 

 Greenstreet, R.E. ; a H'liytr Vhcssa.rA (Euplocamus nycthemerus) 

 from China, presented by Mr. E. J. Beagle; a Small Hill 

 Mynah (Gracula religiosa) from South India, presented by Mr. 

 J. W. Wodler; five Water Ouzels (Cinclus a^uaticus), British 

 Isles, presented by Mr. F. Swabey; an Anaconda (Eunectes 

 murinus) from South America, presented by Mr. G. H. Haw- 

 tayne, C.M.Z.S. ; a Teguexin Lizard (Teius ieguexin) from 

 South America, a Leopard Tortoise (Tesludo pardalis) from 

 South Africa, purchased; a Tamandua Ant-eater (7'amandua 

 tetradaelyla) from South America, a Great American Egret 

 (Ardea egrelta) from America, deposited ; a Reeves's Muntjac 

 (Cervulus reevesi) born in the Gardens. 



RECENT CONTRIBUTIONS TO THE HISTORY 

 OF DETONATING AGENTS \ 



II. 



'T'HAT the power possessed by different very highly explosive 

 substances, of inducing the detonation of such bodies as gun- 

 cotton and nitro-glycerine, is not solely ascribable to the opera- 

 tion of mechanical force very suddenly developed, is indicated 

 not only by the singular inertness of gun-cotton to the influence 

 of nitro-glycerine as a detonating agent, but also by a compari- 

 son of the behaviour of other detonating substances wiih that of 

 the mercuric fulminate, when applied to the detonation of gun- 

 cotton. Thus the detonation of silver fulminate is very decidedly 

 sharper than that of the mercury compound, yet it is in no way 

 superior to the latter in its power as an initiative detonating 

 agent ; indeed, a somewhat larger amount of it appeared to be 

 required than of the mercury salt to induce detonation of gun- 

 cotton with certainty. Again, the iodide and chloride of nitrogen 

 are far more susceptible of sudden detonation than the silver 

 fulminate ; yet while $ grains of the latter, confined in a stout 

 metal envelope, suffice to detonate gun-cotton, 50 grains of 

 chloride of nitrogen confined by water, appeared to be the 

 minimum amount with which the detonation of gun-cotton could 

 be accomplished with certainty, while no success attended the 

 employment of confined iodide of nitrogen in quantities ranging 

 up to 100 grains. 



The incompatibility of these results with the general conclu- 

 sion, based upon numerous and greatly varied experiments, that 

 the facility with which the detonation of gun-cotton and nitro- 

 glycerine, and bodies of a similar character as explosives, is 

 induced by an initiative detonation, is proportionate to the 

 mechanical force aided by the heat developed by the latter, led 

 the lecturer to the conclusion that a synchronism or similarity in 

 character or quality of the vibrations develoi)ed by the detona- 

 tion of particular substances, operates in favouring the detona- 

 tion of one such substance by the initiative detonation of a small 

 quantity of another, while in the absence of such synchronism, 

 a much more powerful detonation, or the apjilication of much 

 greater force, would be needed to effect the detonation of the 

 material operated upon. This view has received considerable 

 support from results since obtained by othtr experimenters, es- 

 pecially by MM. Champion and Pellet ; but the subject is one 

 which still needs further experimental elucidation. 



The physical character of explosive substances, as also the 

 mechanical condition of a mass of the particular explosive sub- 

 stance operated on, are of great influence in determining its 

 behaviour when submitted to the action of an initiative detona- 

 tion. The liquid nitro-glycerine is far more sensitive to detona- 

 tion than gun-cotton ; one grain of mercuric fulminate, confined 

 in a metal case, suffices to detonate nitro-glyctrine « hen sur- 

 rounded by it ; but, in order to attain this re-ult with any degree 

 of certainty, it is necessary so to confine the nitro-glycerine as 

 to prevent its yielding to the blow developed by the initiative 

 detonation, and thus to some extent escai)ing from the operation 

 of the sudden concussion to which the ]iarticlcs contiguous to 

 the fulminate charge arc submitted. 



If nitro-glycerine be mixed with solid tubstances in a fine 

 state of division, plastic mixtures may be obtained, and the liquid 

 may thus be presented in something like a solid form to the 



' Weekly Evening Lecture at the Royal Institution, Friday, March ii, 

 1879. By Professor Abel, C.B., F.R.S. Revised by the Arthur. Cunlinued 



