400 APPENDIX. 



an ample supply of warm clothing, antiscorbutics, preserved meats, 

 &c, in the event of detention, which will be expended in the most 

 judicious manner. 



Wishing you a safe and successful cruise, 



I am, &c, 



Charles Wilkes, 

 Commanding Exploring Expedition. 



P. S. You will, if possible, obtain from Deception Island a self- 

 registering thermometer, said to have been left some time since on the 

 point of the cove. 



To Lieut. Wm. M. Walker, 



In charge of Tender Flying-Fish. 



XXVIII. 



GENERAL INSTRUCTIONS, FOR BOAT DUTY, SURVEYING, ETC. 



Immediately after anchoring in position, you will hoist your dis- 

 tinguishing pennant, keeping it up till every thing is done, such as 

 distance measured, astronomical bearings taken on one of the vessels, 

 the angle between her and the others ; also, angles on any thing 

 remarkable on shore, such as headlands, flag or signal staves, huts, 

 trees, &c. When ready to change your position, haul down your dis- 

 tinguishing pennant ; and when ready to measure the base or distance 

 by sound, which is the first thing to be done after you are in position, 

 hoist your ensign at the fore ; as soon as all the vessels have answered, 

 you will dip it and fire in a few seconds ; run up the ensign again, and 

 repeat firing three times. 



To communicate the elapsed time to this vessel, hoist the distin- 

 guishing pennant of the vessel whose distance is to be shown, and 

 with it the " number" indicating the number of seconds ; the quarter, 

 half, or three-quarters, may be designated by hoisting the first, second, 

 and third repeaters under all, thus — the third repeater under No. 18, 

 would signify eighteen and three-quarters seconds of time. It will be 

 seen, therefore, that when it is necessary to repeat a number, one of a 

 similar denomination must be used, as another signification is given to 

 the repeaters. 



The astronomical bearings may be communicated in the following 

 manner, with the distinguishing pennant of the vessel whose bearing 

 is to be shown : hoist the " number" indicating the degrees with the 



