54 The Royal Observatory of Scotland. 



nearly the whole of the fine weather period of the station 

 might thus be utilised in procuring measures ; which in the 

 autumn would be brought home, computed, and printed, with 

 all the resources of a civilised country. 



" This notable advantage, too, would be gained, without the 

 loss of anything important that could have been secured by 

 remaining in Edinburgh, or rather it would be the means of 

 avoiding a positive loss. For when the College Session closes 

 in April, and the Astronomer has more time to attend to his 

 duties at the Observatory ; exactly then, unhappily, not only 

 does the summer in Scotland prove itself more cloudy than 

 the winter ; but even in clear weather, the nights, owing to 

 the prolonged twilight of a high northern latitude, continue 

 for some months so bright, that little can be done or even 

 attempted, especially with that smaller class of objects, and 

 that more exact observation, in which, as detailed last year, 

 the Director considered himself peculiarly called upon to en- 

 gage with the Equatorial. Just, then, at that season of the 

 year in which the Edinburgh Astronomer has most time at 

 his disposal, clouds and twilight combine to prevent his mak- 

 ing good use of it. 



m Were he, however, enabled to convey the equatorial alone, 

 by a quick journey to a high southern mountain, merely tak- 

 ing with him, be it remembered, his Edinburgh work, neither 

 less nor more, to be executed with greater efficiency, he 

 might reach a country of clearer skies, and darker nights, 

 and be raised high above most of the disturbing influences of 

 the atmosphere. He would, in fact, be able in three months 

 to make more observations there, and each of them of sur- 

 passing excellence, than in a whole year in Edinburgh. Nor 

 does this result depend solely on the theoretical ideas of 

 Newton, for I myself have had unusual opportunity of ob- 

 serving, during some years, on mountains of various heights 

 up to 6700 feet, in a southern country. From which expe- 

 rience, too, I feel justified in concluding, that there would 

 be no difficulty in selecting a station, which should be free, 

 for a given period of the year, from the usual mountain 

 clouds ; and that the degree of increase in the visibility and 

 " steadiness" of the images of the stars in the telescope 



