APPENDIX. 379 
Every opportunity of trying the current must be taken advantage 
of, and marked. 
Astronomical observations, viz., lunar distances of the stars, east 
and west of the moon, of the sun, and of the planets, to be frequently 
taken. 
Observations for chronometers must be taken daily, mornings and 
afternoons, when the weather will permit ; azimuths and amplitudes, 
at least once or twice a day, in the morning, or in the afternoon, and 
the ship's head noted at the same time. 
Any of the officers (among whom are considered the scientific 
gentlemen) will on all occasions promote the objects of the Expedition 
by procuring any article referred to in the foregoing instructions, or 
aiding in carrying into effect the same. And the officer of the deck 
is authorized to stop the ship's w T ay, and perform any evolution with 
a view of carrying into effect the above, in which case he will report 
the same immediately to me, if time does not permit his doing so 
previously. 
It is necessary for the sea-officers to make themselves thoroughly 
acquainted with the heavenly constellations, in order to be efficient in 
noting the course of meteors, &c. 
Charles Wilkes, 
Commanding Exploring Expedition. 
United States' Ship Vincennes, 
At Sea, August 25th, 1838. 
XL 
United States' Ship Vincennes, 
At Sea, August 25th, 1838. 
The undersigned, commanding the Exploring Expedition, in com- 
municating the following instructions, from the Navy Department, 
for the government and information of those under his command, 
directs the particular attention of all persons in the Expedition to the 
same, and especially to that part of them, which prohibits any one 
furnishing to persons not attached to the Exploring Expedition, any 
communications which have reference to the objects or proceedings 
of the Expedition. 
" Although the primary object of the Expedition, is the promotion 
of the great interests of commerce and navigation, yet you will take 
all occasions, not incompatible with the great purpose of your under- 
taking, to extend the bounds of science, and promote the acquisition 
