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By W. D. Barbour, 

 Of the Leeds Astronomical Society. 



AMONGST the myriads of Suns and Planets which throng 

 the vast abysses of celestial space on every side, is it 

 possible to conceive that this little Earth of ours, in pro- 

 portion like a grain of sand or a floating sunbeam mote, is the 

 only spot upon which life has evolved and human-like intelligence 

 dwells ? So extravagant a supposition is not only incongruous to 

 reason and opposed to analogy and continuity, but is also incon- 

 sistent with our conceptions of an all-wise, omnipotent Creator. 

 Thus encouraged by many sanctions, the astronomer could scarcely 

 aspire to a nobler discovery than demonstration, by objective 

 proof, of the existence in yonder skies of intelligent life consti- 

 tuted mentally, if not physically, like ourselves. 



Hitherto, it has been supposed that the main essentials to 

 discovery lay in the size and excellence of the investigating tele- 

 scope. Experience has now shown that, all-important as quality 

 of telescope may be, the condition of the atmosphere through 

 which the light from the planet or star reaches the eye of the 

 observer, is the main factor which determines success. In har- 

 mony with this fact, the careful scrutiny to which Mars has been 

 subjected in recent years, has yielded the best results, not to the 

 largest telescopes, but to those of less aperture when erected in 

 lofty positions away from large populations and atmospheric 

 impurities. But even here, another difficulty confronts the obser- 

 ver which he cannot control. The diverse temperatures and cross 

 currents of the different air strata, extending to many miles above 

 our heads, interfere more or less with direct passage of the light- 

 rays downwards to the telescope. Thus, instead of clearly defined 

 surfaces of planets and round discs of stars, we have blurring in 

 the first instance and distortion in the second. These difficulties 

 the astronomer meets with endless patience and watchfulness, 

 waiting for those brief intervals, often one to three seconds only, 

 when the'-overhead atmosphere is steady and without cross-currents. 



International Journal of Microscopy and Natural Science. 

 Third Series. Vol. VII. i 



