461 Intelligence and Miscellaneous Articles. 



measurement of the dimensions and distances of the fixed stars from 

 ourselves is yet to be found ; and if ever found, it will be through 

 the means of astronomical observation. The influence of all these 

 discoveries upon the condition of man is, no doubt, infinitely diver- 

 sified in relative importance ; but all, even the minutest, contri- 

 bute to the increase and diffusion of knowledge. There is no 

 richer field of science opened to the exploration of man in search 

 of knowledge than astronomical observation ; nor is there, in the 

 the opinion of this Committee, any duty more impressively incum- 

 bent upon all human governments than that of furnishing means 

 and facilities and rewards to those who devote the labours of their 

 lives to the indefatigable industry, the unceasing vigilance, and the 

 bright intelligence indispensable to success in these pursuits." 



Erom the time Commander Maury entered on his duties to the 

 present, the course of the "Naval Observatory" has been one of 

 onward progress. The meteorological work was great ; but a greater 

 astronomical work was proposed, that of assigning to every star in 

 the heavens that could be seen with the observatory instruments its 

 colour, position, and magnitude. This noble work was begun and 

 carried on until 1849, when, the corps of computers proving alto- 

 gether insufficient to keep pace with the observers, it was discon- 

 tinued. Nevertheless much valuable work has been accomplished 

 since, as a reference to the volumes and reports will show. 



We cannot close this notice of the progress of astronomical 

 science in the United States, at one observatory only, without re- 

 ferring to the contemplated extension of optical power in the erec- 

 tion of a refracting telescope of good definition and of 26 inches 

 clear aperture, now in course of construction by Messrs. Alvan 

 Clark and Sons. This instrument is to be completed within four 

 years of the date of contract (June 30, 1871), or thereabouts. 

 Doubtless in the hands of such zealous observers as constitute the 

 staff of the observatory it will do good sendee to astronomical 

 science, and contribute in no small degree to uphold the position 

 now accorded to the United-States Naval Observatory by the spon- 

 taneous verdict of the scientific men of the Old World. 



on the sudden cooling of melted glass, and particularly 

 on " rupert's drops. " by v. de luynes. 



The bursting produced in "Kupert's drops" the moment the 

 thin end is broken off has been hitherto attributed to the state 

 of forced dilatation of the interior. It is supposed that the 

 external layer, suddenly solidified by cooling, while the inner 

 portions are still hot and much expanded, compels the latter, to 

 which it remains adherent, to retain a volume greater than that to 

 which they would be reduced if the whole drop had been cooled 

 slowly ; hence a state of unstable equilibrium, which is only main- 

 tained by the resistance of the outer layers ; so that when this re- 



