British Association, ' 415 



Extracts from the Address of the President of the British Association, 



Rev. Humphrey Llovd, at the Meeting^ Aug. 26, 1857. 



Astronomy. — The career of planetary discovery, ^yliicb began in tLe 

 first years of the present century, and was resumed in 1845, has since 

 continued with unabated ardor; and since 1846 not a single year has 

 passed without some one or more additions to the ninnber of the plane- 

 toids; in one year alone (1852), no fewer than eight such bodies were 

 discovered. The last year has furnished its quota of y??^^, and in the 

 present three more have been found, one by Mr. Pogson, of Oxford, and 

 the other two by M. Goldschmidt, of Paris. The known number of these 

 bodies is now forty-five. Their total mass, however, is vary small. The 

 diameter of the largest is less than forty miles, white that of the smallest 

 (Atlanta) is little more than four. 



These discoveries have been facilitated by star-maps and star-catalogues, 

 the formation of which they have, on the other hand, stimulated. Two 

 very extensive works of this kind are now in progress — the Star-Catalogue 

 of M. Chacornac, made at the observatory of Marseilles, in course of pub- 

 lication by the French Government; and that of Mr. Cooper, made at 

 his observatory at Markree, in Ireland, which is now being published by 

 the help of the Parliamentary Grant of the Royal Society. It is a re- 

 markable result of the latter latK^r, that no fewer than seventy-seven stars, 

 previously catalogued, are now missing. This, no doubt, is to be ascribed 

 in part to the errors of former observations; but it seems reasonable to 

 suppose that, to some extent at least, it is the result of changes actually 

 in progress in the Sidereal System. The sudden appearance of a new fixed 

 star in the heavens, its subsequent change of lustre, and its final disap- 

 pearance, are phenomena which have at all times attracted the attention 

 of astronomers. About twenty such have been observed. Arago has 

 given the history of the most remarkable, and discussed the various hy- 

 potheses which hav^^ been offered for their explanation. Of these, the 

 most plausible is that which attributes the phenomenon to unequal bright- 

 ness of the faces of the star which are presented successively to the earth 

 by the star's rotation round its axis. On this hypothesis the appearance 

 should be periodic. M* Goldschmidt has recently given support to this 

 explanation, by rendering it probable that the new star of 1609 is the 

 same w^hose appearance was recorded in the years 393, 798, and 1203. 

 Its period in such case, is 405^ years. 



The greater part of the celestial phenomena are comprised in the move- 

 ments of the heavenly bodies and the configuration depending on them; 

 and they are for the most part reducible to the same law of gravity which 

 governs the planetary motions. But there are appearances which indi- 

 cate the operation of other forces, and which, therefore, demand the at- 

 tention of the physicist— although, from their nature, they must probably 

 long remain subjects of speculation. Of these, the spiriform nebulae, dis- 

 covered by Lord Eosse, have been already referred to from this chair, as 

 indicating changes in the more distant regions of the uniyei-se, to which 

 there is nothing'^entirely analogous in our own system. These appearan- 

 ces are accounted for, by an able anonymous writer, by the action of 

 gravitatiuir forces combined with the effects of a resisting medium— the 



o 



