PEEFACE. 
One of the most prolific sources of loss to the 
merchant, and, through him, to the world at largo, 
exists in the incorrectness of many of the charts by 
which his ships are sailed. There are also many 
coasts of which we have no charts at all, and there 
are various currents with whose strength and direc- 
tion we do not pretend to he acquainted. 
Besides, there are some few branches of our com- 
mon family of whom we know little or nothing, and 
there is also a vast extent of the earth’s surface yet 
awaiting the first pressure of the explorer’s foot. 
To test the accuracy of charts extant, to prepare 
others of unknown coasts, to follow the trackless 
path of the wayward current, to lift the veil that 
liung between civilization and the customs and habits 
of isolated tribes and nations, and to collect data 
from unfrequented parts of our globe for the advance- 
ment of science, the Government of the United 
