Sept. 7, 1876] 



NATURE 



395 



Our knowledge of aerolites has of ate years been greatly in- 

 creased ; and I cannot occupy a few moments of your time more 

 usefully than by briefly referring to the subject. So recently as 

 i860 the most remarkable meteoric fall on record, not even ex- 

 cepting that of L'Aigle, occurred near the village of New Con- 

 cord in Oliio. On a day when no thunder-clouds were visible, 

 loud sounds were heard resembling claps of thunder, followed 

 by a large fall of meteoric stones, some of which were distinctly 

 seen to strike the earth. One stone, above 50 pounds in weight, 

 buried itself to the depth of 2 feet in the ground, and when dug 

 out was found to be still warm. In 1872 another remarkable 

 meteorite, at first seen as a brilliant star with a luminous train, 

 burst near Orvinio in Italy, and six fragments of it were after- 

 wards collected. 



Isolated masses of metallic iron, or rather of an alloy of iron and 

 nickel, similar in composition and properties to the iron usually 

 diffused in meteoric stones, have been found here and there on 

 the surface of the earth, some of large size, as one defcribed 

 by Pallas, which weighed about two-thirds of a ton. Of the 

 meteoric origin of these masses of iron there is little room for 

 doubt, although no record exists of their fall. Sir Edward 

 Sabine, whose life has been devoted with rare fidelity to the 

 pursuit of science, and to whose untiring efforts this Association 

 largely owes the position it now occupies, was the pioneer of the 

 newer discoveries in meteoric science. Eight and filty years ago 

 lie visited, with Capt. Ross, the northern shores of Baffin's Bay, 

 and made the interesting discovery that the knife-blades used by 

 the Esquimaux in the vicinity of the Arctic highlands were 

 formed of meteoric iron. This observation was afterwards fully 

 confirmed ; and scattered blocks of meteoric iron have been 

 found from time to time around Baffin's Bay. But it was not 

 till 1870 that the meteoric treasures of Baffin's Bay were truly 

 discovered. In that year Nordenskiijld found, at a part of the 

 shore difficult of approach even in moderate weather, enormous 

 blocks of meteoric iron, the largest weighing nearly twenty tons, 

 imbedded in a ridge of basaltic rock. The interest of this ob- 

 servation is greatly enhanced by the circumstance that these 

 masses of meteoric iron, like the basalt with which they are 

 associated, do not belong to the present geological epoch, but 

 must have fallen long before the actual arrangement of land and 

 sea existed — during, in short, the middle Tertiary, or Miocene 

 period of Lyell. The meteoric origin of these iron masses from 

 Ovifak has been called in question by Lawrence Smith ; and it 

 is no doubt possible that they may have been raised by upheaval 

 from the interior of the earth. I have, indeed, myself shown by 

 a magneto-chemical process, that metallic iron, in particles so 

 fine that they have never yet been actually seen, is everywhere 

 diff'used through the Miocene basalt of Slieve Mish, in Antrim, 

 and may likewise be discovered by careful search in almost all 

 igneous and in many metamorphic rocks. These observations 

 have since been verified by Reuss in the case of the Bohemian 

 basalts. But, as regards the native iron of Ovifak, the weight 

 of evidence appears to be in favour of the conclusion, at which 

 M. Daubree, after a careful discussion of the subject, has arrived 

 — that it is really of meteoric origin. This Ovifak iron is also 

 remarkable from containing a considerable amount of carbon 

 partly combined with the iron, partly diffused through the me- 

 tallic mass in a form resembling coke. In cocnection with this 

 subject, I must refer to the able and exhaustive memoirs of 

 Maskelyne on the Busti and other aerolites, to the discovery of 

 vanadium by R. Apjohn in a meteoric iron, to the interesting 

 observations of Sorby, and to the researches of Daubree, 

 Wohler, Lawrence Smith, Tscheimak, and others. 



The important services which the Kew Observatory has ren- 

 dered to meteorology and to solar physics have been fully recog- 

 nised ; and Mr, Ga^siot has had the gratification of witnessing 

 the final success of his long and noble efforts to place this ob- 

 servatory upon a permanent footing. A physical observatory 

 for somewhat similar objects, but on a larger scale, is in course 

 of erection, under the guidance of M. Janssen, at Fontenay, in 

 France, and others are springing up or already exist in Germany 

 and Italy. It is earnestly to be hoped that this country will not 

 lag behind in providing physical observatories on a scjJe worthy 

 of the nation and commensurate with the importance of the 

 object. On this question I cannot do better than refer to the 

 high authority of Dr. Balfour Stewart, and to the views he 

 expressed in his able address last year to the Physical Section. 



Weather telegraphy, or the reporting by telegraph the state of 

 the weather at selected stations to a central office, so that notice 

 of the probable approach of storms may be given to the sea- 

 ports, has become in this country an organised system ; and con- ! 



sidering the little progress meteorology has made as a science, 

 the results may be considered to be on the whole satisfactory. 

 Of the warnings issued of late years, four out of five were justi- 

 fied by the occurrence of gales or strong winds. Few storms 

 occurred for which no warnings had been given ; but unfortu- 

 nately among these were some of the heaviest gales of the period. 

 The stations from which daily reports are sent to the meteoro- 

 logical office in London embrace the whole coast of Western 

 Europe, including the Shetland Isles. It appears that atmo- 

 spheric disturbances seldom cross the Atlantic without being 

 greatly altered in character, and that the origin of most of our 

 storms lies eastward of the longitude of Newfoundland. 



As regards the velocity of the wind, the cup-anemometer of 

 Dr. Robinson has fully realised the expectations of its discoverer ; 

 and the venerable astronomer of Armagh has been engaged during 

 the past summer, with all the ardour of youth, in a course of 

 laborious experiments to determine the constants of his instru- 

 ment. From seven years' observations at the Observatory of 

 Armagh, he has found that the mean velocity of the wind is 

 greatest ift the S.S.W. octant, and least in the opposite one, and. 

 that the amount of wind attains a maximum in January, after 

 which it steadily decreases, with one slight exception, till Juiy, 

 augmenting again till the end of the year. 



Passing to the subject of electricity, it is with pleasure that I 

 have to announce the failure of a recent attempt to deprive 

 Oerstedt of his great discovery. It is gratifying thus to find high 

 reputations vindicated, and names which all men love to honour 

 transmitted with undiminished lustre to posterity. At a former 

 meeting of this Association, remarkable for an unusual attend- 

 ance of distinguished foreigners, the central figure was Oerstedt. 

 On that occasion Sir John Herschel in glowing language com- 

 pared Oerstedt's discovery to the blessed dew of heaven which 

 only the mastermind could draw down, but which it was for others 

 to turn to account and use for the fertilisation of the earth. To 

 Franklin, Volta, Coulomb, Oerstedt, Ampere, Faraday, Seebeck, 

 and Ohm are due the fundamental discoveries of modern electri- 

 city — a science whose applications in Davy's hands led to grander 

 results than alchemist ever dreamed of, and in the hands of 

 others (among whom Wheatstone, Morse, and Thomson occupy 

 the foremost place) to the marvels of the electric telegraph. 

 When we proceed from the actual phenomena of electricity to the 

 molecular conditions upon which those phenomena depend, we 

 are confronted with questions as recondite as any with which the 

 physicist has had to deal, but towanis the solution of which the 

 researches of Faraday have contributed the most precious mate- 

 rials. The theory of electrical and magnetic action occupied 

 formerly the powerful minds of Poisson, Green, and Gauss ; and 

 among the living it will surely not be invidious to cite the names 

 of Weber, Helmholtz, Thomson, and Clerk Maxwell. The work 

 of the latter on electricity is an original essay worthy in every 

 way of the great reputation and of the clear and far-seeing intellect 

 of its author. 



Among recent investigations I must refer to Prof. Tail's dis- 

 covery of consecutive neutral points in certain thermo-electric 

 junctions, for which he was lately awarded the Keith prize. 

 This discovery has been the result of an elaborate investigation 

 of the properties of thermo-electric currents, and is specially 

 interesting in reference to the theory of dynamical electricity. 

 Nor can I omit to mention the very interesting and original 

 experiments of Dr. Kerr on the dielectric state, from which it 

 appears that when electricity of high tension is passed through 

 dielectrics, a change of molecular arrangement occurs, slowly in 

 the case of solids, quickly in the case of liquids, and that the 

 lines of electric force are in some cases lines of compression, in 

 other cases lines of extension. 



Of the many discoveries in physical science due to Sir William 

 Grove, the earliest and not the least [important is the battery 

 which bears his name, and is to this day the most powerful of all 

 voltaic arrangements ; but with a Grove's battery of 50 or even 

 100 cells in vigorous action, the spark will not pass through an 

 appreciable distance of cold air. By using a very large number 

 of cells, carefully insulated and charged with water, Mr. Gassiot 

 succeeded in obtaining a short spark through air ; and lately De 

 La Rue and Miiller have constructed a large chloride of silver 

 battery giving freely sparks through cold air, which, when a 

 column of pure water is interposed in the circuit, accurately 

 resemble those of the common electrical machine. The length 

 of the spark increasing nearly as the square of the number of 

 cells, it has been calculated that with 100,000 elements of this 

 battery the discharge should take place through a distance of no 

 less than eight feet in air. 



