383 



The analyses of felspars from the North of Ireland, quoted 

 by Dr. Apjohn, could not, Sir Robert Kane remarked, have 

 any reference to a question as to the nature of the felspars in 

 the south-east, nor could the crystallographic or analytical de- 

 tails into which Dr. Apjohn had entered. The real question 

 was, the average constitution on the great scale of the granitic 

 district lying to the south of Dublin, and on this Sir Robert 

 Kane considered the conclusions suggested in his former no- 

 tice to be perfectly unimpeached, although in special localities 

 deposits of true potash felspars (orthoses) may occur, a fact of 

 which Sir Robert Kane was, of course, perfectly aware, and 

 never could have contemplated to deny. 



The Rev. Dr. Lloyd read a paper on the magnetic influence 

 of the moon. 



" The influence of the moon upon the position and move- 

 ments of the magnetic needle seems to have been first recog- 

 nised by Professor Kreil. From the discussion of the mag- 

 netical observations made at the Prague Observatory, in 1839 

 and 1840, he has inferred that there existed a small periodical 

 variation in the position of the freely suspended horizontal 

 magnet, dependent upon the position of the moon with respect 

 to the meridian. The question has been again examined, in 

 this and in other bearings, by Mr. Broun, the able Director 

 of Sir Thomas Brisbane's Observatory at Makerstoun, in Scot- 

 land, and the action of the moon has been apparently traced 

 in a variety of periodical laws, dependent not only upon her 

 hour-angle, but also upon her declination and distance from 

 the earth. 



" Notwithstanding the very remarkable nature of the phe- 

 nomenon thus announced, the question has since remained 

 unexamined, and the conclusions unconfirmed, by other ob- 

 servers. Whether the small changes deduced by Professor 

 Kreil and Mr. Broun were thought to be within the limits of 

 the errors of observation, or the apparent improbability of 



