96 British Association for the Advancement of Science. 



rora Borealis, and to record every phenomenon of this nature ; 

 and I have no doubt, from the hsts ah'eady sent me, that this 

 class of observations will be the most complete and valuable that 

 have ever been made." Accompanying this report were tables 

 of hourly observations of the barometer and thermometer (made 

 at Kingussie, 700 or 800 feet above sea level, by Mr. Rutherford) 

 during the 27th, 28th, 29th, and part of the 30th of November, 

 1838 ; the barometer having gradually sunk down to the lowest, 

 27.200, on the 29th at 3 P. M., and risen again rapidly to its usual 

 height after 9 A. M. of the 30th. There were also accounts of 

 three occurrences of the Aurora Borealis, viz. on the 13th and 

 17th of November and 14th of December, 1838. 



A paper was read On the best positions of three magnets, in 

 reference to their 7nutual action, by Rev. H. Lloyd. It is a prob- 

 lem of much importance, in the arrangement of a magnetical ob- 

 servatory, to determine the relative position of the magnetical in- 

 struments in such a manner, that their mutual action may be ei- 

 ther absolutely null, or at least readily calculable. Such the 

 author stated to be the object of the present investigation. The 

 problem may be reduced to this ; to determine the position of the 

 three magnets A, B, and 0, in such a manner, that the resultant 

 actions exerted upon A and B, respectively, by the other two, 

 shall lie in the magnetic meridian. The solution of this problem 

 was shown to be contained in two equations, which may, of 

 course, be satisfied by means of two unknown angles ; so that 

 when we have a greater number of undetermined quantities, some 

 of them remain arbitrary, and the conditions may be fulfilled in 

 various ways. In reply to a question from the President, Mr. 

 Lloyd briefly explained the arrangement of the portable observa- 

 tory, adopted by Capt. J. Ross, in his preparations for the Antarc- 

 tic Expedition. It is so constructed as to form either th?^ee small 

 separate rooms, or one large one. The former arrangement is de- 

 sirable at places where the dip is nearly 90°, and where, conse- 

 quently, the horizontal directive force is very small, and the dis- 

 turbing action of the magnets on one another, relatively great. 

 The parts are connected with copper fastenings ; and the whole 

 is so arranged, as to occupy a very small bulk when in pieces, and 

 to be capable of being put together with quickness and security. 



New Photometer. Prof Daubeny exhibited the model of an 

 apparatus, by means of which, in a more complete condition, he 



