50 
evident, that a great additional precision will be afforded to this 
mode of discovering his place, when astronomical observations are 
not to be had and his reckoning is doubtful. 
I have annexed to this paper a reduced chart of the bank of 
Soundings, on which the various descriptions of bottom above no- 
ticed are distinguished by colours, as far as they can be ascertained 
from our present charts ; and also a series of lines of equal sound- 
ing, at every ten fathoms in succession, from fifty to one hundred 
fathoms. 
In this way, a species of meshwork subdivision of the bank is 
effected, similar to what we obtain by the lines of latitude and lon- 
gitude, or those of equal variation of the compass. 
The chart is necessarily very imperfect, but it illustrates what I 
have in view; and, from the well known zeal and talent of our na- 
vigators, we may look forward confidently to its future improve- 
ment. 
I have pursued the same idea over charts of other portions of the 
ocean, which I may make the subject of a future communication, 
