6 Don J. Rodriguez’s Observations on the 
reduces all angles to the plane of the horizon, and with such 
a degree of correctness, that the error in the sum of the three 
angles of any triangle is scarcely, in any instance, found to 
exceed three seconds of a degree, and in general not more 
than a small fraction of a second. 
Accordingly the geodetical observations were conducted 
with a degree of exactness, which hardly can be exceeded ; 
and even if we suppose for a moment, that the chains made 
use of in the measurement of the bases may not admit of equal 
precision with the rods of platina employed in France, never- 
theless, the degree of care employed in their construction, in 
the mode of using them, and the pains taken to verify their 
measures was such, that no error that can have occurred in 
the length of the base, could make any perceptible difference 
in the sides of the series of triangles, of which the whole ex- 
tent does not amount to so much as three degrees. 
Nevertheless, the results deduced by the author, from this 
measure alone, would lead to the supposition that the earth, 
instead of being flattened at the poles, is in fact more elevated 
at that part than at the equator, or at least, that its surface is 
not that of a regular solid. For the measures of different 
degrees on the meridian, as reduced by Lieut. Col. Mudge, 
increase progressively toward the equator. 
The following table of the different measures of a degree 
in fathoms is given by the author in his Memoir. 
Latitude. 
52 0 50' 30" 
60766 
52 38 56 
60769 
<0 
00 
G* 
60794, 
£2 2 20 
60820 
