224 



Report on Terrestrial Magnetism. 



[July 



blished laws ; since one station (the island of Teneriffe) has already- 

 exhibited some singular anomalies, both in respect to the Dip and 

 Intensity. Under these circumstances it is much to be wished that 

 observations could be multiplied in various parts of India, whereby 

 the law of variation from theory may be detected ; — and how is this to 

 be accomplished ? My answer is ready : — Let any gentleman who is 

 disposed to undertake a set of magnetic intensity experiments signify 

 his intentions ; and I shall have great pleasure in forwarding to him, 

 free of expense, a magnetised and compared needle, provided that I 

 am favored with a copy of the results. In anticipation that there will 

 be several gentlemen disposed to forward this inquiry, I am now pre- 

 paring several needles for use. All that is necessary is, that the per- 

 son applying for a needle should be in possession of a good clock or 

 chronometer, and has the means of ascertaining its daily rate. 

 Madras Observatory, 9th May, 1837. 



Note. — We shall be most happy to promote the author's views by 

 making a series of experiments with his needles in Calcutta, and then 

 distributing them to friends in the interior. Of the dip we have a few 

 records, (see Proc. As. Soc. for May). Major B. Blake also brought 

 from England an adjusted intensity needle, but we have not yet been 

 favored with his observations. — Ed.— Journal of the Asiatic Society 

 of Bengal, No. 65, May 1837, page 374—377. 



3.— Report upon a Letter addressed by M. le Baron de Humboldt 

 to His Royal Highness the President of the Royal Society, and com- 

 municated by His Royal Highness to the Council. 



To His Royal Highness the President and Council of the Royal 



Society.* 



Previously to offering any opinion on the important communication 

 on which we have been called upon to report, we feel that it will be 

 proper to lay before the Council a full account of the communication 

 itself. In this letter M. de Humboldt developes a plan for the observ- 

 ation of the Phenomena of Terrestrial Magnetism worthy of the great 

 and philosophic mind whence it has emanated, and one from which 

 may be anticipated the establishment of the theory of these pheno- 

 mena. 



* This report is taken from the Athenseum of March 1837, 



