ASTRONOMY AND METEOROLOGY. 401 



has adopted the plan of testing the efficiency of his object-glasses when com- 

 pleted, by sweeping for new double stars of the last degree of difficulty, 

 rather than by the examination of objects whoso character was previously 

 known. At first, under the impression that every such object in the north- 

 ern hemisphere visible wi:li telescopes of moderate aperture must already 

 have been picked up and registered during the careful examinations of that 

 portion of the heavens by the Struves with the Dorpat refractor of 9'6 

 inches aperture, and with the Pculkova of fifteen, Mr. Clark confined his 

 search to the southern hemisphere; and his diligence and skill were rewarded 

 by the discovery of several interesting objects, which, it might be supposed, 

 would hardly have escaped the Dorpat telescope if they had been as de- 

 cidedly double in 182G as they are now. Latterly, however, having ventured 

 to extend his researches northward, he has made some discoveries which arc 

 almost startling (especially the duplicity of the very minute companion of p. 

 Herculis), and are sufficient to show that there is much which may be 

 achieved by a diligent use of instruments of moderate dimensions, provided 

 they are also of extreme perfection. 



ON A LAW OF TEMPERATURE DEPENDING UPON LUNAR 



INFLUENCE. 



In a paper on the above subject, read before the Dublin meeting of the 

 British Association, by Mr. J. P. Harrison, the author commenced by saying 

 that, although the question of lunar influence on the atmosphere of our 

 planet was very generally considered as set at rest by the investigations of 

 M. Arago, yet he felt very confident that he was in a position to prove the 

 law he was now about to announce without fear of contradiction. Pie had 

 reduced and thrown into the form of tables and of curves 280 lunations, Avith 

 the corresponding mean temperatures ; and the laws at which he had arrived 

 were ; first, between the first and second octant the temperature immediately 

 after the first quarter, both on the average and also, with rare exceptions, in 

 each individual lunation is higher than the temperature shortly before the 

 first quarter ; secondly, and more particularly the mean temperature of the 

 annual means of the second day after the first quarter (or the tenth day of 

 the moon's age) is always higher than that of the third day before the first 

 i quarter (or the fifth day of the lunation). 



Mr. Fulbrook, of Sussex, England, in a recent communication to the Lon- 

 don Athenaeum, calls attention to the result of his investigations of the 

 moon's position with reference to the plane of the earth's orbit, considered 

 in connection with the rain fall. He says, " I am induced to do this, 

 because I think it is extremely desirable that meteorological observers of 

 other latitudes should investigate this important subject. Should any do so, 

 I shall feel greatly obliged by being informed of the result. The moon oc- 

 cupies about twenty-seven days in passing from any point say her asccnd- 

 inf node round the zodiac to the same arain. During one half of this 



O o O 



time she is in north (celestial) latitude, the other half in south latitude. I 

 took one hundred such lunar courses in due order. The fall of rain during 



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