Nov. 6, 1873] 



NATURE 



first part of the Report is concerned with the six summer 

 excursions of the club in 1872, interesting accounts of the 

 history, antiquities, and natural history of the various 

 places visited being given. Of the papers contained in 

 the volume, we mention the following : — " The Lignite of 

 Antrim and their Relation to the True Coal," by Mr. 

 William Gray, in which the author considers the subject 

 both geologically and economically. The Rev. Dr. Mac- 

 Ilwaine, in a paper on " Life," gives an account of the 

 various theories as to the nature of life held by philo- 

 sophers from the earliest times to the present day. A 

 different aspect of the same subject is discussed in Mr. 

 Robert Smith's paper on " Darwinism," in which the 

 author briefly sketches the nature of the Darwinian theory 

 of development, and gives practical exemplifications of its 

 working in every-day life. Air. William Gray gives an 

 entertaining account of some of the doings of the 

 notorious " Flint Jack " in Ireland ; and the longest paper 

 in the volume, by the Rev. Edmund M'Clure, is one of 

 considerable ethnological value, on " Family Names as 

 indicative of the Distribution of Races in Ireland." The 

 Society offers a considerable number of prizes, competi- 

 tion for which will no doubt tend to encourage the 

 practic.^l study of the various subjects with which the 

 Society is concerned. Altogether it seems to be in a 

 thoroughly healthy condition. 



LETTERS TO THE EDITOR 



[The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. No notice is taken of anonymous 

 cotnmunications. ] 

 Prof. Young and the Presence of Ruthenium in the 

 Chromosphere. 



I H.WE been asked by Prof. Young, of Dartmouth College 

 (U.S.) to say, with reference to the statement made on p. 244 of 

 the third edition of my "Spectrum Analysis" concerning the pre- 

 sence of Ruthenium (Ru) in the solar atmosphere, that possibly 

 by a lapsus calami he may have written the symbol (fib) when 

 giving the information of his discovery to Dr. Huggins, from 

 whom I received a note on the subject. 



Although, in accordance wich Prof. Young's desire, I make 

 these remarks, I cannot help feeling that they are quite unneces- 

 sary, as no one who knows the careful exactitude of Prof. 

 Young's work could for a moment suppose that he was capable 

 of making a confusion between Rubidium and Ruthenium. 



H. E. RoscoE 



Owens College, Manchester, Nov. 4 



Trie Miller Casella Thermometer 



I WAS surprised on readintj Messrs. Negretti and Zambra's 

 letter published in your journal of October 23. 



I was under the impression that it had been conclusively es- 

 tablished that the principle upon which the Casella-Miller or 

 jMiller-Casella Deep-Sea Thermometer is constructed is identical 

 with the one originally made in 1S57 by Messrs. Negretti and 

 Zambra at the suggestion of Mr. Glaisher, F.R..S., by the late 

 Admiral Fitz-R:^y's directions for the Board of Trade. 



I was present when Mr. Scott, P". R.S., Director of the 

 Meteorological Department of the Board of Trade, read a paper 

 upon the suliject at the Meteorological Society, January 17, 

 1872 ; he Slid : — " I submitted one of these instruments, made 

 for the late Admiral Fitz-Iioy, to hydraulic pressure; it proved 

 good and trustworthy. The history of these instruments was 

 perfectly fami'iar to many gentlemen interested in deep-sea 

 soundings in 1869." 



I may add that I saw the original instrument at tlie Ilyilro- 

 graphic Office ten years ago ; in justice I am bound to say that 

 Messrs. Negretti and Zambra were the first manufacturers of a 

 deep-sea thermoTieter unaffected by pressure. 

 , 20S, Piccadilly, Ojt. 29 ' P. Pastoreli.i 



Captain Hutton's "Rallus Modestus" 



In the notice of the current Ibis, which appeared in Vol. viii. 

 p. 519, reference is made to a paper by Captain Ilutton, con- 



tending for the validity of his Rallus modestus, as distinct from 

 R. dieffcnbachii. 



The next number of the Ibis will contain my reply to Captain 

 Hutton's communication. In tlie meantime I will merely state 

 that the whole of his argument rests on the assumption that 

 Rallus dieffcnbachii and R. philippensis are the same, in whicli 

 he is entirely mistaken. 



It is a fallacy, therefore, to suppose that because he has sliown 

 his bird to be distinct from Rallus philifipensis, v.'ith which he 

 compares it, he has proved it to be distinct from Rallus dieffen- 

 bathii, which, by his own admission, he has never seen. 



Oct. 18 Walter L. Buller 



Flight of Birds 



In Nature, vol. viii. p. 86, A[r. J. Guthrie calls attention to, 

 and asks explanation of, a curious plienomenon in the flight of 

 birds observed by him : — "In the face of a strong wind," he 

 says, " the hawk remained fixed in space without fluttering a 

 wing for at least two minutes. After a time it quietly changed 

 its position a few feet with a slight motion of its wings, and then 

 came to lest again as before, remaining as motionless as the 

 rocks around it." 



I have often observed the same phenomenon, but, until re- 

 cently, not carefully enough to warrant any attempt at explana- 

 tion, though always convinced that it was not due to any invisible 

 vibratory motion of the wings, as suggested by Mr. Guthrie. 

 During the past summer, however, while on a tour through the 

 mountains of Oregon. I had a fine opportunity of watching very 

 closely a large red-tailed hawk {Butto montanus) while perlbrm- 

 ing this wonderful feat, and of noting the conditions under which 

 alone, I believe, it is possible. These conditions are precisely 

 those described by Mr. Guthrie, viz., a steady wind, blowing 

 across an tipirard slope, terminated by a ridge. For a half-hour 

 I watched the hawk, with wings and tail widely expanded, but 

 motionless, balancing himself in a fixed position for several 

 minutes in the face of a strong wind ; then changing his position 

 and again balancing, but always choosing his position just above 

 the ridge. 



I explain the phenomenon as follows : — The slope of the hill 

 determines a slight up'.vard 6.aec\.\on to the wind. The bird in- 

 clines the plane of his expanded wings and tail very slightly 

 dozvuzvards, but the inclination is less than that of the 'wind. 

 Under these conditions it is evident tliat the tendency of gravity 

 would be to carry the bird forioard and doiomuard, while the 

 wind would carry him bachward and uptuard. The bird skilfully 

 adju.sts the plane of his wings and tail, so that these two 

 opposing forces shall exactly balance. He changes his place and 

 position from time to time, not entirely voluntarily, but because 

 the varying force or direction of the wind compels him to seek a 

 new position of equilibrium. Joseph Le ContE 



Oakland, Cal., U.S., Sept. 19 



Collective Instinct 

 In response to the appeal which closes Mr. Buck's interesting 

 letter (N.vture, vol. vid.p. 332), the following instance of" collec- 

 tive instinct" exhibited by an animal closely allied to the woU, viz., 

 the Indian jackal, deserves to be recordef. It was communicated 

 to me by a gentleman (since deceased) on whose veracity I can 

 depend. Tnis gentleman v/as waiting in a tree to shoot tigers 

 as thev came to drink at a Urge lake (I forget the district) 

 skirted by a dense jangle, when about midnight, a Urge Axis 

 deer emerged from the latter, and went to the water's edge. 

 Then it stopped and sniffed the air in the direction of the jungle, 

 as if suspecting the presence of an enemy ; apparently satisfied, 

 however, it began to drink, and continued to do so lor a most 

 inordinate length of time. When literally swollen with water 

 it turned to go into the jungle, but was met upon its extreme 

 margin by a jackal, which, with a sharp yelp, turned it again 

 into the open. The deer seemed much stariled, and ran along 

 the shore for some distance, when it again attempted to enter 

 the jungle, but was again met and driven back in the same 

 manner. The night being calm, my friend could hear this 

 process being repeated time after time — the yelps becoming 

 successively fainter and fainter in the distance, until they became 

 wholly inaudible. The stratagem thus employed was sufficiently 

 evident. The lake having a long narrow shore intervening 

 between it and the jungle, the jackals formed themselves in line 

 along it, while concealed within the extreme edge of the cover; 



