338 MAGNETIC SURVEY OF A PART OF THE SOUTHERN HEMISPHERE. 
completion of the survey might receive the attention which they appeared to him to 
merit. These letters were submitted by the Committee to the Council of the Royal 
Society, with a recommendation that an application should be made by the President 
and Council to the Lords Commissioners of the Admiralty, to authorize the comple- 
tion of the southern survey in the manner suggested. 
The Board of Admiralty having been pleased to accede to this request, the 
“ Pagoda,” a bark of 360 tons, was hired at the Cape of Good Hope by the Admiral 
commanding on the station, and was fitted for a voyage of some months duration, 
receiving a complement of four officers and thirty-eight seamen from the flag-ship. 
Lieut. T. E. L. Moore, of the Royal Navy, who had been one of the officers of Her 
Majesty’s ship Terror in the Antarctic Expedition, and was consequently accustomed 
to the navigation of the high latitudes, as well as practised in magnetic observations, 
(having taken a very prominent share in those of Her Majesty’s ship Terror, recorded 
in Nos. V. and VI. of these Contributions,) was selected to command the Pagoda, 
and instructed to cooperate with Lieut. Clerk, and to give him every assistance and 
support in the execution of the service on which they were jointly employed. At the 
time of his appointment, Lieut. Moore was serving in the Caledonia at Lisbon, and 
some little delay occurred in his recall, and also in his subsequent departure from 
England, in consequence of which he did not join the Pagoda at the Cape until the 
4th of January, when she had been some days ready for sea. 
It may be useful to officers desirous of making magnetic observations on board 
ship, to be acquainted with the precautions which, at the period in question, were 
deemed desirable for the employment of magnetic instruments on board ship under 
the most advantageous conditions, and for eliminating the disturbing effects of the 
ship’s iron : a copy of the instructions with which Lieut. Clerk was furnished is there- 
fore subjoined 
Instructions for Lieut. II. Clerk, R.A . , on points connected with the Magnetic Obser- 
vations on Board Ship. 
<( 1. Influence of the Ship's Iron. — Before the ship is fitted, you had better select, in 
concert with the naval officer appointed to command her, suitable positions for the 
standard compass and for your Fox. They should both be on the midship line of the 
ship ; the standard compass sufficiently high to see well over the bulwarks when 
taking azimuths : the Fox lower for the sake of steadiness : it is generally found con- 
venient to use the Fox a few feet in front of the standard. When the positions have 
been chosen, have any iron that may be near them removed, (as far as can con- 
veniently be done,) and do not let any fresh iron be placed within at least six feet of 
either of them. 
“ When the ship is perfectly ready for sea, take a day for the determination of the 
effect of the ship’s iron on the standard compass. You are already acquainted with 
the usual process of doing this, and are furnished with the printed instructions issued 
