The Presidenft Address, 283 



will doubtless, as he himself expects, discover many new 

 features in those interesting objects. It is to the influence 

 of Lord Rosse's example that we are indebted for the fine 

 reflecting telescope of Mr Lassell, of which I have already 

 spoken ; and it is to it, also, that we owe another telescope, 

 which, though yet unknown to science, I am bound in this place 

 especially to notice. I allude to the reflector recently con- 

 structed by Mr James Nasmyth, a native of this city, already 

 distinguished by his mechanical inventions, and one of a 

 family well known to us all, and occupying a high place 

 among the artists of Scotland. This instrument has its 

 great speculum 20 feet in focal length, and 20 inches in dia- 

 meter ; but it difl^ers from all other telescopes in the remark- 

 able facility with which it can be used. Its tube moves ver- 

 tically upon hollow trunnions, through which the astrono- 

 mer, seated in a little observatory, with only a horizontal 

 motion, can view at his ease every part of the heavens. 

 Hitherto, the astronomer has been obliged to seat himself at 

 the upper end of his Newtonian telescope ; and if no other 

 observer will acknowledge the awkwardness and insecurity 

 of his position, I can myself vouch for its danger, having 

 fallen from the very top of Mr Ramage's 20 feet telescope 

 when it was directed to a point not very far from the zenith. 

 Though but slightly connected with astronomy, I cannot omit 

 calling your attention to the great improvements — I may 

 call them discoveries — which have been recently made in 

 Photography. I need not inform this meeting that the art of 

 taking photogi'aphic negative pictures upon paper was the 

 invention of Mr Fox Talbot, a distinguished member of tliis 

 Association. The superiority of the Talbotype to the 

 Daguerreotype is well known. In the latter the pictures are 

 reverted, and incapable of being multiplied, while in the 

 Talbotype there is no reversion, and a single negative will 

 supply a thousand copies, so that books may now be illus- 

 trated with pictures drawn by the sun. The difl&culty of 

 procuring good paper for the negative is so great, that a 

 better material has been eagerly sought for ; and M. Niepce, 

 an accomplished officer in the French service, has success- 

 fully substituted for paper a film of albumen, or the white of 

 an egg, spread upon glass. This new process has been 



