MAGNETIC SURVEY OF GREAT BRITAIN. 



59 



The mean of the nine results in the preceding table is 68° 56'* 1 . 

 Each angle is a mean of four readings. Total number of read- 

 ings, 272. 



Table V. (In two parts) contains observations made by Cap- 

 tain Edward Johnson, R.N., F.R.S., and myself, with the same 

 circle and needle, in the Regent's Park, London, on the 15 th 

 and 16th November, 1837- In this case, the reversal of the 

 needle on its supports was made a part of the sei'ies, in addition 

 to the reversals in the last table ; thus the values of i and i' are 

 each the mean of eight angles instead of four. 



Table V. 

 Observations with Capt. Fitz Roy's Gambey, Regent's Park, London. 

 Observer, Captain Johnson. 1837. 



