12 Photography at Greenwich Observatory. 



observers and writers go beyond the definite information con- 

 veyed by such markings, and ascribe to glaciers the function 

 of digging all the gigantic hollows in which the great lakes of 

 Europe and America now repose, we may prefer exercising 

 due caution, and not be too ready to accept explanations 

 which have rather the aspect of overriding a favourite hobby 

 than that of calmly considering all the circumstances that have 

 to be explained. There is a tendency in philosophers to follow 

 a practice common amongst physicians, and to have their pet 

 causes, just as the latter indulge in their favourite remedies. 

 At one time it may happen that patients seeking medical aid 

 are all mercurized, bismuthized, or iodized, according to the 

 fashion of the hour, and in like manner geologists indulge in 

 fiery or watery speculations, sometimes neglecting and some- 

 times exaggerating the action of any particular agency capable 

 of forming or changing terrestrial rocks. Mr. Campbell is a 

 decided worshipper of the spirits of ice. Within the limits we 

 • have indicated we highly esteem his labours, and in taking 

 leave of his Fire and Frost, we wish him health and oppor- 

 tunity for further travel, and that he may bring home and 

 publish as valuable a series of sketches as those which will 

 give permanent importance to the work he has just produced. 



PHOTOGRAPHY AT (GREENWICH OBSERVATORY. 



BY THOMAS W. BUER, F.R.A.S., P.C.S., ETC. 



The scientific operations carried on at the Royal Observatory 

 are essentially of a practical and utilitarian character. Ori- 

 ginally founded for the especial purpose of the improvement of 

 navigation by the construction of accurate catalogues of stars 

 and tables of the moon, it is highly to the credit of its succes- 

 sive directors that they have never been tempted to a diversion 

 of its resources to objects more immediately attractive and 

 likely to bring them fame and renown as discoverers of fresh 

 heavenly bodies, or other additions to the wonders of 

 astronomy. 



It is to this steady devotion to the original purpose of the 

 establishment that we are indebted for the great work of 

 Flamsteed, his Historia Ccelestis ; for the indefatigable ob- 

 servations of Bradley, and his great discoveries of aberration 

 and nutation; the well -conceived plans and constant labours 

 of Maskelyne, who started the Nautical Almanack on its 

 useful career ; the instrumental improvements and exact 

 observations of Pond ; and last, but not least, the laborious 



