I/O 



NATURE 



\_yiine 24, 1880 



and has a most wonderful provision for preventing the erosion of 

 the banks and for adding to the dry land . It is a squat bushy, 

 tree, and round tlie stem, to an extent equal to the spread of its 

 branches it sends up thickets of straight shoots a foot or two 

 hio-h. These, when the tide is up or the water in flood, catch all 

 the stray branches, leaves, gras-, &c., that may be floating about, 

 and also promote silt. I3y this contrivance, therefore, not only 

 are the banks protected from the distinctive action of water, but 

 also raised and consolidated. Again, as regards Mr. Stoney's 

 observatimof calcareous masses in timber, which was brought 

 to the notice of the Asiatic Society of Bengal in 1S70 as a fresh 

 discovery, it seems strange that the learned body in ques- 

 tion did not know that the existence of such concretions, 

 so far from being very rave, is an occasional and well known 

 phenomenon. Tlius, in the Madras Joitnial of Literature a}iJ 

 Science for April-September, 1S5S, page 142, Prof. Mayer gi\cs 

 a qualitative analysis of a concretion of tlie kind found in a teak 

 log. It consisted chiefly of magnesia, v ith potash, lime, silica, 

 and a trace of iron. The substance, he says, "Must be looked 

 on as a mixture, and not a true chemical compound." Again, 

 he observes, "as a whole the substance thus hardened is insoluble 

 in cold, and but slightly so in water of higher temperature. At 

 212", however, there is sen-ible action after a time. In dilated 

 hydrochloric acid solubility ensues, hastened by increased tempe- 

 rature. .Solution is attended by slight effervescence, some 

 carbonic acid being liberated." He then proceeds to give an 

 explanation of the process by which sach mineral matters may 

 be taken up from the soil and deposited in the tree. So far as I 

 know the occurrence of such concretions in India was first brought 

 to notice by Lieut., now Col. Ilawkes, of the Madras Army, in 

 1S58. He had seen them only in teak logs, and remarked that 

 they generally occur "iti what carpenters call a shake in the 

 wood, but with this exception the logs are perfectly sound, and 

 no communication whatever \s\\\\ the external air has been 

 observed." G. Eidie 



Government Central Museum, Madras, May 13 



Remarkable Discovery of a Murder in Bermuda 

 The following account of a murder which was committed in 

 Bermuda in the autumn of 1878 is taken from a letter written 

 to Gen. Sir J. H. Lefroy, C.B., F.R.S,, lately Governor of 

 these islands, and author of the " Annals of Bermuda," by the 

 Attorney-General of the islands, Mr. S. Brownlow Gray. The 

 mode of discovery of the crime is so remarkable that I think it 

 ought to be put on record, and Sir J. H. Lefroy has kindly per- 

 mitted me to make extracts from the letter for that purpose. I 

 believe no account of the circumstances of the case has as'yet been 

 published in Europe. There .seems to be no likelihood as to 

 mistake regarding the facts. The special occurrence could 

 probably only happen in the tropics in warm water. 



H. N. MOSELEY 



" In the atitumn of 1878 a man committed a terrible crime in 

 Somerset, which was for some time involved in deep mystery. 

 His wife, a handsome and decent mulatto woman, di-appeared 

 suddenly and entirely from sight, after going h jme from church 

 on Sunday, October 20. Suspicion immediately fell upon the 

 husband, a clever young fellow of about thirty, but no trace of 

 the missing woman was left behind, and there seemed a strong 

 probabihty that the crime would remain undetected. On Sun- 

 day, however, October 27, a «eek after the woman had disap- 

 peared, some Somerville boatmen looking out towards the sea, 

 as is their custom, m ere struck by observing in the I-ong Bay 

 Channel, the surface of which was rufiled by a slight breeze, a 

 long streak of calm such as, to Uie their own illustration, a cask 

 of oil usually diffuses around it when in the water. The feverish 

 anxiety about the missing woman suggested some strange con- 

 nection between this singular calm and the mode of her disap- 

 pearance. Two or three days after — why not sooner I cannot 

 tell you — her brother and three other men went out to the spot 

 where it was observed, and from which it had not disappeared 

 since Sunday, and with a series of fish hooks ranged along a 

 long line dragged the bottom of the channel, but at first without 

 success. Shifting the position of the b jat, they dragged a little 

 further to windward, and presently the line was caught. With 

 water glasses the men di-coveredthat it had caught in a skeleton 

 w-hich was held down by some heavy weight. They pulled on the 

 line ; something suddenly gave way, and up came the skeleton of 

 the trunk, pelvis, and legs of a human body, from which almost 

 every vestige of flesh h.ad disappeared, but which, from the 



minute fragments remaining, and the terrible stench, had 

 e\iJently not lain long in tlie water. The husband was a 

 fisherman, and Long Bay Channel was a favourite fishing- 

 ground, and he calculated, trnly enough, that the fish would very 

 soon destroy all means of identification ; but it never entered into 

 his head that as they did so their ravages, combined with the 

 process of decomposition, would set free the matter which was to 

 write the traces of his crime on the sui face of the water. The 

 case seems to be an exceedingly interesting one ; the calm is not 

 mentioned in any book on medical jurisprudence that I have, 

 and the doctors seem not to have had experience of such an 

 occurrence. A diver went down and found a stone with a rope 

 attached, by which the body had been held down, and also 

 portions of the scalp and of the skin of the sole of the foot, and 

 of clothing, by means of which the body was identified. The 

 husband \ias found guilty and executed." 



On the Simplest Continuous Manifoldness of Two 

 Dimensions and of Finite Extent 



There appeared in your p-ages some three years ago (vol. xv. 

 p. 515) an article of mine " On the Simplest Continuous Mani- 

 fjldness of Two Dimensions and of Finite Fxtent." In a 

 succeeding number a correspondent (Mr. Monro, of Bamet) pro- 

 pounded a query which may be shortly stated as follows : — 

 " How does it happen that the perpendicular on a geodesic from 

 a point moving along another geodesic clianges sign without 

 passing through either the value zero (o) or the value infinity 

 (cc)?" The problem here suggested is a peculiarly knotty one. 

 In the case of the Euclidian plane the perpendicular of course 

 changes sign by passing through the value «, while in the case 

 of a spherical surface it is equally obvious that the perpendicular 

 passes through zero, since the two geodesies intersect twice. But 

 what are we to say of the strange hybrid surface a\ hich formed 

 the subject-matter of my paper ? Your correspondent appeared 

 to insinuate that the problem was insoluble, and that the definition 

 of tlie surface must therefore involve a logical contradiction. For 

 a while I was gi-eatly puzzled by this unforeseen difficulty, but 

 after a little thought came to the conclusion that the perpendicular 



changes sign by passing through the value — \'^^, where / is 



r, 2 



positive and represents the absolute length of a complete geodesic. 

 In other words, I conceived that the sign of the perpendicular 

 changed from -f to - by a continuous vari ation of the real 

 numbers a and i5in the complex number a -f b\J _ i- I conceived 

 a to diminish continuously till, passing through o, it became - a, 

 while /' at the same time increased with simple harmonic motion 

 from o to a maximum, and then decreased from a maximum 

 to o. 



I was, however, not sufficiently clear on the matter to feel 

 justified in addressing you until I received, the other day, a copy 

 of a paper by Prof. Simon Newcomb, of the United States 

 Observatory, entitled "Elementary Theorems relating to the 

 Geometry of a Space of Three Dimensions and of Uniform 

 Positive Curvature in the Fourth Dimension." ^ The subject- 

 matter of this masterly paper is in reality the simplest continuous 

 manifoldness of tliree dimensions and of finite extent. It there- 

 fore naturally includes all tliat had been worked out in my own 

 paper and a little more besides. In particular it throws strong 

 light on the difficulty raised by your correspondent. For an 

 exactly parallel anomaly presents itself in the theory of ^ Prof. 

 Newcomb's solid space, and is stated in his 13th Prcpooition as 

 follows :— " The tioo sides of a complete plane - are not distinct, 

 as in a Euclidian surface." If a being were to travel along a 

 coaiplete plane in a geodesic line, he would, on his return, find 

 himself on the opposite side of the plane to that on v\hich he 

 started, and would have to repeat his journey in order to regain 

 his original poise. " In this property," Prof. Newcomb says, 

 "we find a certain amount of reason for considering the com- 

 plete plane as a double surface." The corresponding anomaly 

 in space of two dimensions — i.e., the specific feature noticed as 

 an anomaly by your correspondent — is then explained as Propo- 

 sition XIV. : " The following proposition is intimately connected 

 with the preceding one. If, moving along a right line, we erect 

 an indefinite seric, ot perpendiculars, each in the same Eucfidian 

 plane with the one which precedes it, then, on completing the 



I Abdnick au5 dem Journal fiir die reine uiid auge-waiuite Matlumatik, 

 Bd. 83. Druck von G. Relmer in Berlin. 



' A •' camplelc pl.ine " is a geodesic surface of Prof. Newcombs space. 

 Il is in all respects identical with the surface treated of in my paper. 



