348 



NArjJR^ 



[August 12, 1897 



horse, pig, red deer, and domestic fowl ; al$o an abundance of 

 shells of oysters, cockles, mussels and limpets, with many pot- 

 boilers or burned stones. It is pointed out that bones of 

 this extinct bird have been found in the kitchen-middens of 

 Denmark, in one or two places in Scotland, in Durham, and on 

 the North American coast. More recently, they have been 

 found on the County Antrim coast. Mr. Ussher's find corro- 

 borates this discovery, and shows that the range of the Great 

 Auk extended in Ireland nearly as far south as 52° N. latitude. 



A NUMBER of interesting navigational instruments were 

 exhibited at the Fishmongers' Hall last week. The exhibition 

 was organised by a sub-committee of the Shipmasters' Society, 

 with Captain D. Wilson-Barker as chairman, and was princi- 

 pally intended to illustrate the progress that has been made in 

 the art of navigation during Her Majesty's reign. Altogether 

 there were about 200 exhibits, some of which are of historic 

 importance. Included among these was a sextant, by Bird, said 

 to have been used by Captain Cook. There was a well selected 

 xiumber of charts and navigation books, among the exhibitors in 

 this section being Admirkl Sir W. J. L. Wharton, F.R.S. The 

 Meteorological Society lent several meteorological instruments 

 .such as are in use at sea, while in contrast with the quadrants, 

 sextants, compasses, &c., which did duty in 1837, instruments 

 •of a more modern date were on view, comprising some of Lord 

 Kelvin's inventions, such as the deflector for adjusting the com- 

 pass without swinging the ship, the vertical force instrument, 

 .and the sounding machine. Sections were also devoted to 

 ships' models and pictures, ancient charts and books, and ancient 

 instruments. 



The Pilot Chart of the North Pacific Ocean for August, pub- 

 lished by the American Hydrographic Office, contains a large 

 amount of information useful to navigators. In addition to the 

 «sual arrows showing the prevalent direction and force of the 

 wind and the drift of the currents, there is a forecast of the 

 wind and weather which may be expected during the month, 

 and also a chart showing the mean atmospheric conditions at 

 •Greenwich mean noon, any large variation from which may 

 indicate a coming gale. As this is the season of maximum fre- 

 >quency of typhoons, as shown by the table compiled by Dr. 

 Doberck, of the Hongkong Observatory for the thirteen years 

 1883-96, a special notice of these storms is given. Attention is 

 ■drawn to the fact that the typhoon of the Western Pacific is in 

 many respects the counterpart of the West Indian hurricane in 

 the Atlantic. Both cla.sses of storms have their origin in the 

 vicinity of tropical groups of islands, and, under similar baro- 

 metric conditions, both undergo the same slow development, 

 •and exhibit the same tendency to recurve upon reaching the 

 northern limit of the north-east trades. 



Some facts of interest in connection with gold-wa.shing on the 

 Saskatchewan River are stated in the Report of the Geological 

 Survey of Canada for 1895 (^'o'- viii. new series) just i.ssued. 

 The principal paying bars are found along the river within a 

 distance of about sixty miles above and a similar distance below 

 Edmonton. It is pointed out, however, that the occurrence of 

 gold is not limited to the North Saskatchewan, the metal being 

 found, in greater or less abundance, on portions of the courses 

 of all the rivers east of the Rocky Mountains from the forty- 

 ■ninth parallel northward. 



The auriferous character of the rocks of the Huronian system 

 in Canada has been established by mining operations of recent 

 jears. The economic importance and generally metalliferous 

 character of Huronian rocks was recognised by Sir William 

 Logan in reports of the Canadian survey made nearly forty 

 years ago. Referring to this. Dr. Dawson says in the latest 

 report : " It is gratifying to observe that the practical miner is 

 NO. 1450. VOL. 56] 



liQW beginning to appreciate the value of a large amount of 

 geological work carried out in the country to the north of the 

 Great Lakes, which, a few years ago, it might have appeared 

 difficult to justify in the light of any economic results up to that 

 time achieved. There can now be very little doubt that every 

 square mile of the Huronian formation of Canada will sooner or 

 later become an object of interest to the prospector, and that 

 industries of considerable importance may yet be planted upon 

 this formation in districts far to the north, or for other reasons 

 at present regarded as barren and useless." The conclusions 

 which Dr. Dawson arrived at as to the richness of the Yukon 

 district, after his exploration of it in 1887, have lately been so 

 strikingly established by the discovery of large quantities of 

 gold on the Klondyke River, that his suggestions as to the com- 

 mercial value of Huronian rocks will probably receive the 

 attention of the mining world. 



In the Bulletin de T Acadimie des Sciences de Cracovie, Dr. 

 L. Natanson gives a kinetic theory of the equations of vortex- 

 motion of fluids. This investigation is of special interest, 

 inasmuch as it takes account of a certain molecular property to 

 which the name " constraint of perturbations " {coercition des 

 perturbations) has been applied. As long ago as 1845, ^^ 

 connection of the laws of vortex-motion with the principle of 

 moments was pointed out by Sir G. G. Stokes. Dr. Natanson's 

 paper may be said, in a certain sense, to be a development of 

 this idea, in that he shows how the equations of Helmholtz and 

 Nanson can be verified by supposing the so called "forces of 

 constraint " to satisfy the equations of angular momentum. 



A NEW cable recorder, invented by M. Ader, is described in 

 La Nature of July 24. It consists essentially of a fine wire 

 stretched vertically in a magnetic field created by a strong hori- 

 zontal electro-magnet, the poles of which surround the wire. 

 The currents from the cable traverse the wire, which moves to 

 the right or left — that is, towards the north or the south pole of 

 the electro-magnet— according to their direction. A shadow of 

 the wire is projected across a slit, behind which a band of 

 photographic paper travels. A black spot thus falls upon the 

 paper, and as the wire moves to the right or left the movements 

 are traced upon the photographic paper by the shadow of the 

 spot, the result being a record similar to that given by the 

 syphon recorder. The paper is developed automatically in three 

 baths contained in a small dark chamber, and the signals are 

 shown in white upon a black ground. As to the speed obtained, 

 350 letters a minute, that is, about seventy words, have been re- 

 corded through the cable between Marseilles and Algiers, and 

 150 letters per minute have been recorded upon the Brest-New 

 York cable, the transmitter being at St. Pierre-Miquelon, and 

 the receiver at Brest. 



In July of last year, Prof. Eschenhagen, of Potsdam, pre- 

 sented to the Berlin Academy a preliminary note on certain 

 small variations of the earth's magnetism, which he had then 

 detected for the first time. The apparatus then used consisted 

 of a unifilar magnetometer, in which the magnet, a small steel 

 mirror, was made to lie perpendicularly to the magnetic 

 meridian by the torsion of the suspending quartz fibre. An 

 account of further researches on the same subject is now given 

 in the Berliner Sitzungsberichte. The most important oscil- 

 lations have a period of about thirty seconds, and are observed 

 chiefly between 6 a.m. and 6 p.m., i.e. roughly speaking, when 

 the sun is above the horizon. Since October last waves of 

 shorter period, lasting about twelve to fifteen seconds, have 

 only been observed on two days, viz. November 7, 1896 and 

 February 4, 1897 ; but the.se were of only half the amplitude of 

 the normal waves. On several occasions, however, groups of 

 waves were observed which could readily be accounted for by 

 interference, as they closely resembled beats in acoustics. From 



