136 



F. J. Sidney, LL. D., then moved, and J. E. Waller, LL. D., se- 

 conded, the following amendment :— That such articles as it may be 

 thought by the Council desirable to lend be forwarded for exhibition in 

 the Museum, South Kensington, London, belonging to the Science and 

 Art Department of the Committee of Council on Education, during the 

 forthcoming International Exhibition of 1862. 



A. division having taken place, it appeared that there were 24 votes 

 for, and but 7 against, the amendment, which was accordingly declared 

 by the President to be carried. 



The Lord Chief Baron then moved, and the Rev Professor Jellett 

 seconded, as an addition to the amendment : — That, in executing the 

 amendment which has been now passed, the Council have due regard to 

 the safety of the articles selected for transmission to London, and the 

 means to be adopted for their transmission, and for their secure custody 

 there. This motion, having been put by the President, was adopted. 



MONDAY, APRIL 28, 1862. 



The Veky Eev. Chaeles Graves, D. D., President, in the Chair. 



Mr. F. J. Foot read a paper " On the Botanical Peculiarities of the 

 Burren District, county of Clare." 



The Eev. H. Lloyd, D. D., D. C. L., read the following paper: — 



On Eabth-cueeents in connexion with Magnetic Disturbances. 



In a paper recently communicated to the Academy, the author showed that 

 the regular diurnal changes of the horizontal component of the earth's 

 magnetic force are due to electric currents traversing the earth's crust, 

 these currents operating as disturbing forces, which cause the magnets 

 to deviate from their mean positions according to known laws. This 

 relation being once established, the diurnal laws of the Earth-currents 

 may be inferred from their effects. It was thus ascertained that the 

 azimuth and the intensity of the currents varied throughout the day, 

 according to certain laws depending upon the hour-angle of the sun. 

 At different parts of the globe these laws were found to exhibit certain 

 well-marked features in common; while their differences were accounted 

 for, in many instances, by the geographical and physical characters of the 

 region in which they occur. The author now proceeds to extend the 

 same inquiry to the currents which produce the magnetic disturbances. 



It has been shown, by the labours of Kreil, Sabine, and others, that 

 the disturbances of the magnetic elements are subject to periodical laws, 

 depending upon the hour, which are constant for a given place, and for a 

 given season of the year. The sums of the changes produced by these 

 disturbances, at each hour of observation, have been calculated by Ge- 

 neral Sabine for three of the British Colonial Observatories. The cor- 

 responding quantities have been deduced by Dr. Lament, for Munich ; by 

 Mr. Broun, for Makerstoun, in Scotland; and by the author, for Dublin. 



