262 



REPORT — 1861. 



small throughout the experiments to require corrections to be applied on 

 their account. The constant P, depending upon the distribution of magnet- 

 ism in the deflecting and suspended magnets (the same magnets having been 

 used throughout), was determined by the experiments in Table IV. made at 

 Kew by Mr. Chambers : — 



Table IV. — Deflections with Collimator 5 at distances 0*9 ft. and 1*2 ft. to 

 determine the value of P. Observed by Mr. Chambers. 



The experiments detailed in Tables V. and VI. were made with Collimator 

 No. 5, in June 1858, and in January and March 1859, by Messrs. Welsh and 

 Chambers, to determine the value in British units of the magnetic force at 

 the Kew Observatory, adopted as the base station of the Survey. 



Table V. (see opposite page). 



Table VI — Conclusions from Table V. 



