Miscellanies. 179 



^' February 15, 1839. — The officers and council to whom was refei-- 

 red the letter of Doctor Warren, of Boston, inclosing a circular from 

 a meeting of gentlemen at Boston, on the subject of the formation of 

 an American Association for the Promotion of Science, submitted 

 the following resolution, which was adopted by the Society. 



Resolved, That the American Philosophical Society, having given 

 the most respectful attention to the letters laid before them by Doctor 

 W. E. Horner, and to the circular letter from the Committee of 

 gentlemen of Boston, by referring the first letter to a Special Commit- 

 tee, and the second, with the circular, to the Board of Officers, are of 

 the opinion, founded on the Reports of the Committee and of the 

 Officers, that it is inexpedient for this Society to imdertake the organ- 

 ization of an Association, such as is alluded to in these communications. 



Doctor Patterson read an extract from a letter from Mr. T. R. Peale, 

 dated November 13th, 1838. 



In this letter Mr. Peale states, that observations had been made on the 

 night of the 12th — 13th of November, on board of the exploring ves- 

 sel, the Peacock, (place not given,) relating to the number of meteors. 

 The greatest number supposed to have been observed in any one 

 hour was seventy-one. Mr. Peale expresses his doubts whether, from 

 the motion of the vessel on the night in question, it was possible to be 

 accurate on this point, and believes the number to have been much 

 overrated. 



A display of the Aurora Australis had been witnessed a few weeks 

 before the date of the letter. 



Professor A. D. Bache called the attention of the Society to a very 

 convenient method for determining the magnetic dip and intensity, 

 by one instrument, proposed by Professor Lloyd, of Dublin, and used 

 by him. Major Sabine, and Captain James Ross, in the recent mag- 

 netic surveys in Great Britain. 



The approximate dip is observed without disturbing the magnetism 

 of the needle. The angle with the horizon, when the centre of grav- 

 ity of the needle is removed from the axis by a small weight, is also 

 observed, the needle being in the plane of the magnetic meridian. 



To the first observation, a correction is applied, from observation 

 at a station where the dip is accurately known, to obtain the true dip. 

 The second being repeated at different places, the elements necessary 

 to determine the relative intensities are known ; and the approximate 

 formula, connecting these observed elements with the relative intensi- 

 ties of the magnetism of the places where the change of intensity is 

 not great, is very simple. 



Prof. Bache showed an instrument, made by Robinson, of London, 

 of the usual construction, for determining the magnetic dip, with nee- 

 dles for the employment of Professor Lloyd's method. He also re- 



