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THE POPULAR SCIENCE MONTHLY 



the present state of our acquaintance with the configuration of its sur- 

 face, is not generally understood. When, however, the attention of 

 astronomers is more generally directed to the study of the lunar sur- 

 face, Science will he greatly the gainer, as it is there that the past 

 and future of our earth is to be learned. 



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SIZE OF THE PRINCIPAL TELESCOPES IN THE WORLD. 



IN Les Moncles, January 20, 1876, appeared a list of the principal 

 telescopes of the world, with their apertures and focal lengths. 

 It was defective in regard to its enumeration of American telescopes, 

 and in other respects, as all such lists must be. We have compiled 

 from it, and from other sources available, a larger list, which is itself 

 manifestly incomplete, but which will give a better idea of the num- 

 ber of telescopes available, or soon to be available, for astronomical 

 purposes. It is a melancholy fact that the return from so many in- 

 struments, that is, the interest from so much astronomical capital, is 

 not so great as it should be, and it suggests the question as to whether 

 future benefactors of American colleges, for example, will not do bet- 

 ter to provide astronomers to use the telescopes already constructed 

 than observatories in which to put new ones. In the second column, 

 the first name is that of the maker of the objective or speculum, the 

 second that of the engineer who mounted the telescope. 



I. Reflectors. 

 One French inch = 12 Paris lines ; one English inch = 11.26 Taris lines ; one metre = 443.30 Paris lines. 



OWNER OR DIRECTOR, 

 AND OBSERVATORY. 



Lord Posse, Birr Castle. 

 Wm. Herschel, Slough .. 

 Lassell, Liverpool, etc... 



Ellery, Melbourne 



Le Verrier, Paris 



Lord Kosse, Birr Castle.. 



Tisserand, Toulouse 



Stephan, Marseilles 



II. Draper, near N. York 



Lassell, Maidenhead 



W.&J. Herschel, Slough, 



and Cape Good Hope. 



H, Draper, near N. York. 



Maclean, Tunbridgc Wells 



Pritoliard, Oxford 



Worthlnaton and Baxen- 

 dell, Manchester 



Hirst, New Zealand. 



REMARKS. 



Out of use. 

 Destroyed. 



Silvered glass. 



Silvered glass. 



Silvered glass. 

 Silvered glass. 

 Metal. 



Several mirrors. 



Silvered glass. 



and many others. 



