Sept. 16, 1875] 



NATURE 



435 



His advocates, however, and he himself in his later papers, 

 appeal to pressures within the earth enormously greater than 

 those obtained by the mechanical contrivances used, and consider 

 that proportionately greater heat may be evolved. 



My " Remarks " at the Geological Society, now published in 

 The Journal, were primarily framed with reference to Mr. 

 Mallet's paper as it stjod, although I think they are a tolerably 

 satisfactory reply even to the theory as now extended. I have, 

 however, lately gone into the question on first principles, and 

 have satisfied myself that, accepting the conditions lately assumed 

 by Mr. Mallet as a basis, the theory can be shown to be unte- 

 nable. I hope that a paper containing the grounds of my con- 

 clusion will shortly appear. 



I am unable to understand how Mr. Green proposes to account 

 for the development of forces as productive of heat through 

 means of "the gravitation of the whole mass" (of the earth) 

 •'to itself," otherwise than by "the gravitation of the surface 

 upon a retreating nucleus ; " because, unless room be given by 

 a retreating nucleus for the parts to descend, there can be no 

 motion, and consequently no heat. O. Fisher 



P.S. — Upon further consideration of Mr. Green's letter, it 

 strikes me that he has misunderstood my meaning in a way that 

 I did not at first perceive. He says that I "object to the possi- 

 bility of assuming high local temperatures to be produced by 

 the transformation of tangential forces into heat within the earth's 

 crust ; " as if I objected to any localisation. What I did object 

 to was, not a localisation of work and heat, but a localisation 

 within a localisation, such that the heat of crushing a certain 

 localised volume should fuse a further localised portion of the 

 crushed volume. 



Harlton, Cambridge, Sept. II 



Important Discovery of Remains oi Cervus megactros in 

 Ireland 



During 1847, when draining a bog at Kellegar among the 

 Dublin mountains, as many as thirty heads of C. tne^aceros, 

 together with a perfect head and antlers of a Reindeer, were dis- 

 covered in a cutting of about 100 yards, by 3 yards in breadth. 

 They were found as usual in the marl and clay under the bog. 

 I visited this locality in March last, and from the aspect of the 

 ground and evidence of a farmer who remembered the spot where 

 the above were dug up, it seemed probable that by running a series 

 of trenches parallel with the original ditch made in 1847, fresh 

 exuviae might be discovered. The subject was accordingly 

 brought to the notice of the Royal Irish Acidemy, and a grant 

 of 25/. obtained. The result has been the finding of about thirty 

 additional heads of Cervus megaceros, besides numerous detached 

 bones not yet luUy determined. 



Mr. R. J. Moss, Keeper of Mimerals in the museum of the 

 Royal Dublin Society, who volunteered to conduct the explora- 

 tions, writes to me that he found the remains embedded in about 

 two to three feet of clay, and often either lying on or impacted 

 between blocks of granite as if they had been drifted into the 

 above situation. A log of oak three feet in length was dis- 

 covered among the bones in the same stratum of clay. In this 

 instance, as generally obtains in Ireland, the cervine exuviae are 

 met with around the maigins of the bogs, and n«t in the middle, 

 as if the animals were mired in shallow water, or else their carcases 

 had drifted with the winds or currents to the sides and outlets of 

 the lake. Mr. Moss had to stop excavations in consequence of 

 the grant having become expended, so that doubtless many more 

 remains await further explorations. 



This is not the only case known to me of the accumulation of 

 carcases in a small space. I just lately examined a large assort- 

 ment of skulls and bones of C. megaceros dug out of a bog 

 on the property of Mr. R. Usher, of Cappagh, near Dungarvan. 

 These were collected in a space of about ICX3 yards in length and 

 70 yards in breadth. They include heads and cast antlers of no 

 less than fifteen individuals of the great horned deer {i.e. thirteen 

 male and two female skulls), besides the cast antler of a Red 

 Deer. The above were likewise found more towards the side 

 than the centre of the marsh. 



It seems difficult to account for these accumulations of deers' 

 carcases, unless we suppose that a herd was mired on attempting 

 to cross the lake. The fully developed burr of the antler so 

 generally observed on this deer's horns discovered in the mud of 

 ancient lake^ might indicate that their owners perished in aututiin 

 during the rutting season, when doubtless many far grander 

 scenes than those depicted in the "Challenge" and Wolf's "Race 



for Life " occurred along Irish lakes. The Bear and Wolf being 

 the only large carnivores in Ireland during the Pleistocene period 

 may account for the abundance of C. megaceros ; moreover, we 

 have it on historical evidence that the Wolf was extremely 

 common during the seventeenth century, and it is probable, 

 having neither the Hyaena nor the large Felidie to compete with, 

 that it might have hunted ihs great horned Deer into the lakes, 

 where many would have got mired in the deepening mud along 

 their margins. A. Lkith Adams 



Magnus's "Elementary Mechanics" 

 With reference to the favourable notice of my " Elementary 

 Mechanics " which appeared in last week's Nature, I shall be 

 glad if you will permit me to state that the second edition of my 

 book is already in the printers' hands, and that the few errors, 

 chiefly clerical, in the answers to the examples, which you were 

 good enough to point out, are therein corrected. 

 London Philip Magnus 



Sanitary State of Bristol and Portsmouth 



Your correspondent. Dr. Black, in accounting for the uni- 

 formly low death-rate of Portsmouth, has, I venture to suggest, 

 omitted two somewhat important coefficients. The one is a 

 thorough and well-planned system of drainage and outfall, com- 

 pleted some few years since at a cost of about 150,000/. ; the 

 other is the presence of a floating population of several thousand 

 healthy adult males in the shape of the garrison and the sailors. 



E. J. E. 



Lancaster Gate, W., Sept. 11 



OUR ASTRONOMICAL COLUMN 



Binary Stars. — Mr, J. M. Wilson has communicated 

 measures of 2 2107, 44Bootis, and f Aquarii, made at the 

 Temple Observatory, Rugby, in 1871-75, from vi^hich the 

 following are selected : — 



2 2107 i872'49 Pos. 2io°o Dist. o"77 



1873-48 ,, 207 -5 ,, 07 est. 



1874-65 „ 208 -4 „ o 7 est. 



1875-58 „ 215 -5 „ o -5 est. 



44 Bootis 1873-25 „ 240 -6 „ 5 '3 



CAquarii 1873-79 „ 335 -I „ 3 -58 



The binary character of the first of these stars is well 

 supported by Mr. Wilson's measures ; the angular velocity 

 appears to have regularly increased since about the year 

 1850, due allowance being made for the difficulty of the 

 object. Struve's first epoch (a correction being made to 

 the time as printed in " Mensuras Micr.") is 



1829-01 Pos. i48°-6 Dist. i"-i27 



A discussion of the elements of the orbits of o- Coronae, 

 T Ophiuchi, y Leonis, ( Aquarii, and 36 Andromedae, by 

 Dr. Doberck, of Col. Cooper's Observatory, Markree, 

 forms Part 19 of volume xxv. of the Trajisactioris of 

 the Royal Irish Academy. Dr. Doberck employs the 

 graphical method proposed by Sir John Herschcl, which 

 has been so generally applied, at least in the earlier part 

 of the work. Correction of the approximate elements 

 thus obtained by equations of condition will lead to satis- 

 factory results where there are reliable single epochs, or a 

 sufficient number of contiguous ones, to enable us to form 

 normals. It may be questioned whether the additional 

 labour of calculation which some of the methods of calcu- 

 lating double-star orbits that have been proposed neces- 

 sarily involve, is rewarded by more satisfactory results 

 than can be obtained by the application of Herschel's 

 graphical process in the first instance, following up by 

 equations of condition. 



The Zodiacal Light. — During the past week has 

 appeared Z0diacallicht-Beobachiun^en in der letzten 29 

 Jahten 1847- 1875, by Prof. Heis, forming the first special 

 publication of the Royal Observatory of Miinster. It 

 contains in considerable detail, but on a systematic plan, 

 the particulars of the numerous observations made by 



