448 APPENDIX. 
4th. The officers who have no night-watch will be called upon for 
measuring distances during the night. 
5th. The master will be informed in time, when opportunities 
occur for making observations for amplitude, in the morning and 
evening. 
6th. The results of each officer, signed by him, will be sent to the 
commander daily, and entered by his clerk in a book of observations, 
who will note the time when required. 
(Signed) Charles Wilkes, 
Commanding Exploring Expedition. 
U. S. Ship Vincennes, 
At Sea, July 16th, 1839. 
U. S. Ship Vincennes, 
At Sea, August 2d, 1839. 
Sir, 
When you suppose your vessel at her designated distance, you will 
hoist your ensign for firing, which will be answered as soon as seen. 
It is believed that when the Vincennes' masthead subtends an 
angle of 25', you will be three miles from her. 
After the signal is made to take stations, you will pursue that 
course which will lead you to it as soon as possible. 
Immediately after the signal being made to measure azimuths, 
observations will be taken between the sun and vessels, during the 
taking of which observations, the ship's ensign will be hoisted at the 
peak. 
You will, after we heave-to for the night, try the dipping-needles 
and deep-sea temperature. 
You will calculate the time, so as to be near the flag-ship at night- 
fall, and any signals that are made will be repeated to the vessel 
farthest off. In case of appearance of bad weather, you will at once 
draw to close order of sailing unless otherwise directed. 
It is desirable that all calculations should be made before the day 
closes. The current should be tried daily, either morning or evening. 
I am, &c, 
Charles Wilkes, 
Commanding Exploring Expedition. 
Captain Wm. L. Hudson, 
U. S. Ship Peacock. 
