3 66 



NATURE 



[Atigust 1 6, 1 88; 



The canal which it is proposed to make, connecting the Medi- 

 terranean and Red Sea via the Dead Sea and Gulf of Akaba, will, 

 if carried out, throw considerable light upon the theory discussed 

 by Mr. J. Starkie Gardner in your issue of August 2 (p. 323). 

 The low-lying area which this scheme would submerge occupies 

 the greater part of the Jordan Valley, and extends some distance 

 to the south of the Red Sea, where the depression is at least 

 1300 feet. If there is any truth in the theory which ascribes 

 elevation and depression to the denudation of rock from one area 

 and its accumulation upon another, the introduction of such an 

 immense weight of water from the Gulf of Akaba into the Jor- 

 dan Valley will cause considerable subsidence in its vicinity. To 

 what extent this would be the case it is difficult to say, but 

 even a slight subsidence would much facilitate the cutting of 

 the Mediterranean end of the canal. 



Derby, Mill Hill, August 4 R. Mountford Deeley 



"The Speke and Grant Zebra" 



About four months ago I wrote Mr. Joseph Thomson, the 

 explorer who was selected by the Royal Geographical Society 

 to examine the snow-clad mountains in Eastern Africa, and I 

 requested him to look out for the "Speke and Grant" zebra 

 mentioned in Nature of April 26 last by Sir Joseph Fayrer, and 

 I have had the following reply from Mr. Thomson, dated Mom- 

 bassa, June 6, 1883 : — 



" With regard to your two questions I am happy to say that I 

 can give you satisfactory answers. 



" Within the last month I have seen hundreds of zebras, and 1 

 have shot three — one female and two males. The ground colour 

 is white and the legs are striped to the hoofs. Of these facts I 

 am certain, but to make quite sure I shall take care to note their 

 characteristics in detail on my return. I did not know it was a 

 subject of dispute. " 



The subject of dispute referred to is that the French z >ologist, 

 M. Milne-Edwards named a zebra after the President of the 

 Republic, E. Grezyi, which appears to be no other than the 

 animal which we shot twelve of in 1860-63. J. A. Grant 



19, Upper Grosvenor Street, W., August 10 



The Fisheries Exhibition 



The allusion that you made to the marine invertebrates in our 

 department led one of your scientific readers immediately to 

 examine them. He was surprised to find them properly ar- 

 ranged, classified, and named, with a few exceptions. All the 

 alcoholic specimens were looking bright and beautiful. The speci- 

 mens of the marvellous Alcyonaian of British Columbia, Usteo- 

 cella, Gray, or Verrillia Blakeii, as it is called by tho.-e who have 

 sent it, are in a state of perfect preservation. They are not so 

 well accommodated as I could wish, owing to their great length, 

 6 or 7 feet ; still they are to be seen very distinctly, doubled up 

 in a glass jar, 3 feet 5 iuches in height, filled with strong alcohol 

 clear as w ater. The fine specimen of Cryptochiton stelleri, col- 

 lected and contributed by His Excellency the Marquis of Lome, 

 was also found by your reader to be properly exhibited in a con- 

 venient glass jar, and labelled inside and out. The large and 

 interesting collection of marine invertebrates exhibited by the 

 Government of the Dominion of Canada is formed of collections 

 contributed by the Museum of McGill College, Montreal, Laval 

 University, Quebec, and from the Nova Scotia Provincial 

 Museum. The collection of Edible Mollusca was made by the 

 late John R. Willis, of Halifax, N.S. 



Canadian Department, I.F.E., D. HoNEYMAN 



August 7 Canadian Commissioner 



Birds and Cholera 



Allow me to relate an anecdote in point. I was with a regi- 

 ment, to which at the time I belonged, in Mauritius, when that 

 bright and beautiful isle was desolated by Asiatic cholera in the 

 year 1854. It was the subject of common remark that during 

 the prevalence of the epidemic the Indian Minah-bird or star- 

 lings — "martins" they used to be called in the island — aban- 

 doned, or seemed to abandon, the main barrack square and other 

 open spaces they were wont to frequent in the neighbourhood of 

 Port Louis, and were nowhere to be seen. These birds had 

 been imported from India many years before, and were protected 

 as destroyers of certain insect pests in the sugar-canes. They 

 were correspondingly tame in their habits. Presently they betook 



themselves to the forest or Grand Bois, remaining in the centre 

 of the little island ; they could not have left by sea. They reap- 

 peared, or seemed to us to reappear, when the sickness passed 

 away. Mauritius was then one of the stations where meteorological 

 observations were systematically recorded. I rather think that 

 the disappearance of the birds from the haunts of men during 

 the epidemic and their reappearance when it ceased were duly 

 noted by the Colonial Meteorologist, the late Col., then Lieut., 

 A. B. Fyers, Royal Engineers, in his report. At any rate, I 

 distinctly remember his noting another circumstance, viz. that 

 the decline of the cholera mortality in the island, which was 

 sudden and maiked, was coincident with a marked change in the 

 electric condition of the atmosphere at Port Louis, as indicated 

 by the pith-ball electroscope. 



I venture to suggest that the collection and investigation of 

 trustworthy meteorol >gical data during the prevalence of epi- 

 demics and of collateral information bearing thereupon has not 

 yet received as much attention as it deserves from observers out- 

 side the medical profession. II. M. C. 



August 10 



M. Wolf's New Apparatus 



The short abstract given in Nature (p. 336) of the 

 Comptes rcinius for July 23, contains a mistake in respect to 

 M. Wolf's paper " Sur un appareil a l'etude des mouvements 

 du sol." It is stated that M. Wolf's apparatus involves the 

 same principle as that by which my brother and I magnified the 

 displacements of the vertical. This is not the case, since he uses 

 an ingenious arrangement of reading by reflection from mercury. 

 In the abstract in Nature "sol "has been translated "sun" 

 instead of "soil." G. II. Darwin 



Trinity College, Cambridge, August 9 



Double Shadows 



One cloudless evening lately, while walking on a hillside near 

 the southern shore of Loch Etive, Aygyllshire, facing the setting 

 sun, I observed each member of our little company cast a doubl ; 

 shadow on the upward slope of the hill ; first, the usual complete, 

 well defined shadow cast in clear sunshine ; and second, a longer 

 fainter shadow of the upper part of the figure, extending for 

 some distance in the same line beyond the first. The explana- 

 tion was not far to seek. The loch beneath us was perfectly 

 calm, and reflected the sun's disk with dazzling brilliancy. Thi 

 second shadow was evidently produced by tbe reflected rays, 

 thus : — 



. A 



The phenomenon must be of frequent occurrence, but I do not 

 remember seeing it noticed. I shnuld add it was only observable 

 for a few yards at a particular part of the hillside ; a little higher 

 or a little lower it ceased to be visible — doubtless because in the 

 one case the reflected rays fell short, and in the other passed 

 overhead. D. B. 



Glasgow, August 2 



Regnard's Incandescent Lamp 



Herr von Petersen, the engineer of the Zoological Station 

 in this town, recently having occasi jn to use a powerful light, took 

 advantage of the apparatus described in Nature (vol. xxvi. p. 10S) 

 under the name of Regnard's Incandescent Lamp. He used the 

 apparatus figured ad described in Nature, but neither with 

 air forced through petroleum or benzine, nor even with gas 

 forced through the same liquids, could he raise the platinum wire 

 cage to more than a dull red heat, and the flame was never more 

 brilliant than an ordinary Bunsen burner. The experiments 

 were repeated several times with slight variations, but always 

 with the same result. 



I have written this letter at the request of Herr von Petersen, 

 as you do not generally publish communications in a foreign 

 language. Arthur E. Shipley 



Stazione Zoologica Napoli, July 26 



