Jan, 13, 1876] 



NATURE 



219 



is supported by a vertical wall towards Villejuif and surrounded 

 by a low rampart. Hence it is suggested that in all probability 

 the advantage of the gun at Montlhery was due to its being fired 

 over this parapet, whUe that at Villejuif was fired from the level 

 ground. 



The fact that the wind blowing from Villejuif did not reverse 

 this advantage, suggested the possibility that at night, when the 

 diminution of temperature is downward, a light wind may not 

 produce the same effect upon sound as when the diminution of 

 temperature is upward, as it generally is during the day. 



To ascertain if this is the case, some observations were made 

 on some calm nights in May and June of the present year, from 

 which it was found : — 



(i) That the sky was cloudy and there was no dew. The 

 sound of an electric bell i foot above the grass could always be 

 heard further with the wind than against it ; but 



(2) That when the sky was clear and there was a heavy dew, 

 the sound could invariably be heard as far against a light wind 

 as with it, and in some cases much further. On one occasion, 

 when the tempeiature at i foot above the grass was 38' and at 

 8 feet 47^, and the speed of the wind was i foot per second at 

 5 feet above the grass, the bell was heard 440 yards against the 

 wind and only 270 with it. 



Since, therefore, on the nights of the experiments at Villejuif 

 and Montlhery it is stated that the sky was clear, that there was 

 dew, and the temperature recorded at the two stations shows the 

 diminution to have been downwards, it is argued that the effect 

 of the wind to render the sound less audible at Villejuif was 

 completely balanced by the downward refraction of temperature. 



Another phenomenon recorded by Arago is, that while the 

 report's of the guns at Montlhery as heard at that station were 

 attended with prolonged echoes, this was not the case with those 

 at Villejuif. It is thought that this difference is sufficiently 

 accounted for by the fact that while Montlhery is surrounded by 

 high hills with precipitous or wooded sides, which must produce 

 echoes, the country in front of Villejuif is very flat and has not a 

 tree upon it for miles. 



In concluding the paper reference is made to the Appendix to 

 the last Report of the American Lighthouse Board, in which 

 Dr. Henry, the Chairman, gives an account of his experiments, 

 extending over thirty years, and the conclusions to which they 

 have led him ; both of which are in favour of the apparent 

 stoppage of the sound being due to refraction. 



Zoological Society, Jan. 4. — Prof. A. Newton, F.R.S., 

 vice-president, in the chair. — An extract was read from a letter 

 addressed to the Secretary by Mr. George Brown, dated Port 

 Hunter, Duke of York Island, stating that he had shipped for 

 the Society to the care of Dr. G. Bennett, of Sydney, two casso- 

 waries and some other birds from New Britain and Duke of 

 York Island. — A letter was read from Mr. R. Trimen, Curator 

 of the South African Museum, Cape Town, containing some 

 remarks on Canis chania. — Dr. Hector, F. R.S., exhibited and 

 made remarks on three ancient feather-mats, made by the Maoris 

 of New Zealand, which had been obtained by Dr. Buller, from 

 a chief on the Upper Wanganui River. — Prof. W. H. Flower, 

 F. R. S. , gave a description of the skull of a fossil species of the 

 genus Xiphodon, Cuvier, from a specimen belonging to the 

 Museum of the Royal College of Surgeons, supposed to have 

 been found near Woodbridge in Suffolk. — Prof. Huxley, F.R.S., 

 read a paper on Ceratodus, in which he jwinted out the special 

 characters presented by this remarkable fish in the structure of 

 its nasal apertures, brain, skulJ, and fore-limb. Prof. Huxley 

 also called attention to the close connection shown by certain 

 details of structure between Ceratodus and the Chimaeroid fishes, 

 especially as regards the skull. — A communication was read from 

 Dr. Julius Von Haast, F.R.S., containing the description of a 

 new Ziphioid whale from the coast of New Zealand. — Mr. Sclater 

 read a paper on some additional species of birds from St. Lucia, 

 West Indies, which had been sent to him by the Rev. J . E. 

 Semper of that island. The collection contained one very re- 

 markable form which appeared to be referable to a new genus of 

 Mniotiltida:, and was proposed to be called Leucopeza semjjeri. — 

 A communication was read from Mr. W. H. Hudson containing 

 some notes on the spoonbill of the Argentine Republic. — A paper 

 was read by Messrs. Sclater and Salvin, on Peruvian birds col- 

 lected by Mr. Whitely, being the ninth of a series of communica- 

 tions on this subject. — A communication was read from Dr. Otto 

 Fmsch, containing notes on some Fijian birds, including descrip- 

 tion of a new genus and species proposed to be called Drymo- 

 chara badiceps. — Mr. A. H, Garrod read a note on the cmcum 



coli of the Capybara, as observed in a specimen recently deceased 

 in the Society's menagerie. 



Royal Microscopical Society, Jan. 5. — Mr. Chas. Brooke, 

 F.R.S., vice-president, in the chair. — Messrs. W. A. Bevington 

 and B. D. Jackson were elected auditors of the Society's accounts, 

 and a list of gentlemen nominated for election as officers and 

 council for the ensuing year was read by the Secretary. — Atten- 

 tion was called to a niunber of specimens sent to the Society a 

 short time since by Mr. Hanks, of San Francisco, and which had 

 since been mounted for the cabinet by Mr. Loy ; also to some 

 slides of Aulacodiscus kittoni, presented by Mr. Thos. Curties 

 firom material collected on the late Congo Expedition, by Mr. 

 Martin, H.M.S. SpUeJul. — Mr. C. Stewart then gave an 

 interesting account of the structure and development of sponges, 

 freely illustrating his remarks by drawings upon the black-board, 

 and concluded by stating his reasons for believing that the well- 

 known perforations in oyster-shell were really made by the 

 sponge. — Mr. Hickie exhibited to the meeting some photc^raphs 

 from Germany of Navicula crassinervis and Frvstulia saxonica, 

 and read some letters from Dr. Rabenhirst and Herr Seibart in 

 support of his opinion that the two were widely distinct. 



Entomological Society, Jan. 5.— Sir Sidney Smith Saun- 

 ders, C.M.G., president, in the chair. — Messrs. F. J. Homiman 

 and D. G. Rutherford were elected ordinary members, and Prof. 

 W. Dickion, of Glasgow University, and Mr. F. Enoch were 

 elected subscribers. — The Rev. R. P. Murray exhibited a collec- 

 tion of Lepidoptera taken by himself on the Higher Alps, 

 amongst which were some interesting mountain varieties. — Mr. 

 S. Stevens exhibited a specimen of a dragonfly, rare in this 

 country {^schnia mixta), which he had picked up, nearly dead, 

 in his garden at Upper Norwood, in the middle of November. 

 — Mr. Champion exhibited some rare British Coleoptera. — Mr. 

 H, W. Bates communicated a paper entitled " Additions to the 

 list of Geodephagous Coleoptera of Japan, with synonymic and 

 other remarks." — Mr. W. H. Miskin, of Queensland, communi- 

 cated a description of a new and remarkable species of moth 

 belonging to the genus Attacus, of which a male and a female 

 specimen had been taken in the neighbourhood of Cape York. 

 He had named the species A. Hercules. The expanse of the 

 wings measured nine inches, and the hind wings were fiumished 

 with tails. The specimens had been deposited in the Queens- 

 land Museum. — Mr. C. O. Waterhouse forwarded a paper on 

 various new genera and species of Coleoptera belonging to the 

 Geodephaga, A^ecrophaga, Lamtllicornia, and Rhyncopkara, — 

 Part IV. of the " Transactions " for 1875 was on the table. 



Manchester 



Literary and Philosophical Society, Dec. 14, 1875. — Mr. 

 Edward Schunck, F.R.S., &c., president, in the chair. — On 

 graphic methods of solving practical problems, by Prof. Osborne 

 Reynolds. In the first part of this paper it is pointed out that, 

 when dealing with practical problems by the aid of the graphic 

 method, it is not necessary to break off the operations of draw- 

 ing, and find numerical values for the quantities represented, in 

 order to perform on them the operations of multiplication and 

 division. For by the aid of a parallel ruler the operations of 

 multiplication and division may be performed graphically with 

 great facility. The only geometrical proposition involved being 

 that of finding a fourth proportional to three distances. When 

 two distances have to be multiplied or divided the one by the 

 other, a third distance is chosen equal to unity, and a fourth pro- 

 portional found which represents the product or ratio of the first 

 according as unity is the first or third of the given quantities. 

 The method was illustrated as applied to the determination of 

 areas, centres of gravity, and moments of inertia. In the second 

 part of the paper a graphic method is described by which the 

 velocity and acceleration of a moving point can be determined 

 when the times at which it occupies certain positions are known, 

 i.e. the curves representing the velocity and acceleration of the 

 point may be drawn from the curve representing the positions of 

 the point. Also a converse method by which the position of a 

 point at any time may be found from the curve representing 

 either its velocity or displacement. — On explosions of fire- 

 damp. E. W. Biimey, F. R. S. , said that the fearful loss of life 

 in our coal-mines deserved the careful attention of aU societies 

 like ours. It ought to be one of the objects of science to endea- 

 vour to find out the cause of these explosion?, and to devise some 

 means to prevent their cccurrence or lessen their frequency. No 

 doubt Government inspection had been of service, and the ex- 

 amination of managers would tend to improve the efficiency of 



