PROGRESS OF ASTROi^OMICAL PHOTOGRAPHY. 



FROM THE MONTHLY NOTICES OF THE ROYAL, ASTROVOMIUAL SOCIETY, FEBRUARY 14, 



1862. No. 4. 



ADDRESS DELIVERED BY THE PRESIDENT, DR LEE, ON PRESENTING THE GOLD 

 MEDAL OF THE SOCIETY TO MR. WARREN DE LA RUE. 



Gentlemen : In the report which has been read to yoii, you have 

 been informed that the council have assigned the gold medal of the 

 society to our worthy secretary, Mr. Warren De La Rue ; and, as it 

 is the custom, it becomes now my duty to explain to you, in a few 

 words, the grounds of their decision. 



You know that for many years Mr. De La Rue has devoted the 

 energies of his mind, a large expenditure, and such leisure as he 

 could abstract from the complicated cares of an extensive and well- 

 known commercial concern, to the earnest cultivation and systematic 

 pursuit of practical astronomy, and that he has been one of the most 

 frequent contributors to our evening meetings, upon a variety of 

 subjects — all requiring much knowledge, skill, and labor in their 

 treatment. 



Discoveries in the regions of science so crowd upon us in our own 

 times, that valuable inventions and striking results soon fade from the 

 memory, and are lost in the brilliancy of those which rapidly succeed 

 them. 



I must therefore request your indulgence whilst I lay before you 

 what it is that Mr. De La Rue has done to entitle him to receive, and 

 which justifies the council in awarding him the liighest honor that it 

 is in the power of the Royal Astronomical Society to bestow. 



Mr. De La Rue has not only conducted the usual observations 

 which are made at most private observatories, but he has directed 

 the resources of a rare mechanical genius to improvements in the 

 most approved methods of polishing the specula of reflecting tele- 

 scopes, and perfecting the mechanical arrangements by which opera- 

 tions of such refined nicety are performed. 



On this subject there can be no higher authority than Sir John 

 Herschel, who, in an article on the telescope, published in the Ency- 

 doprjcdia Britannica, says : 



"Such is Mr. De La Rue's mechanism, which has afforded very 

 admirable results in the production of specula 13 inches in aperture 

 and 10 feet focal length, the perfection of which is enhanced by his 

 practice of bestowing the same care and precision on every step of 

 figuring of the speculum, from the grinding, the smoothing on a bed 

 of hones, or rather a slab of slate cut into squares, carefully brought 

 to the same figure, and to the figuring of the polisher itself, which 

 being thus previously rendered almost perfect, the speculum is saved 



