432 APPENDIX. 



by azimuthal angles and sound, as by a base of verification. The 

 deck-boards are now sent on board the flag-ship, where the work is 

 calculated and plotted. 



The survey of the island thus represented, which is about seven 

 miles in length, was performed in three hours and thirty-five minutes. 

 It began, as noted on the deck-boards, at l h 18 m p. m., and the observa- 

 tions closed at 4 b 53 m p. m. 



INSTRUCTIONS RELATIVE TO THE DECK-BOARD. 



The deck-board will be kept strictly according to the formula here- 

 with sent. 



The officers of the deck will be particular in marking the times at 

 which any of the vessels change their position, and the length of time 

 they remain in them (by ship's time) ; also the times that the firing 

 takes place. 



The measured angles will be at once communicated to this ship. 



The original deck-paper, with the calculated azimuth results, will be 

 sent to me at the expiration of the day's work, a copy of which will 

 be made previously, and kept on board. 



The particular attention of the officers is required to the " Instruc- 

 tions for Boat Duty, Surveying, &c," of the 22d of February, 1839, 

 also to the Manual of Surveying. 



Charles Wilkes, 

 Commanding Exploring Expedition. 



U. S. Ship Vincennes, 



At Sea? August 15th, 1839. 



XLII. 



U. S. Ship Vincennes, 



At Sea, August 25th, 1839. 

 Sir,— 



I was surprised to notice this evening, that the boats from the 

 Peacock were not alongside at sunset, as there are positive written 

 orders to that effect, unless the boats are previously recalled by signal. 



I presume, also, that the officers of the boats had no authority from 

 you to land, although I saw several on shore, which must have caused 

 some delay in regard to those engaged on surveying duty, a service 

 second to none in the Expedition ; besides hazarding a difficulty with 



