of an Arc of the Meridian . 385 
longest meridional arc in Britain, free from any apparent ob- 
struction. And I was led to select Dunnose for one of its extre- 
mities, as observations made there, in conjunction with others 
at Greenwich, would enable me to make corrections of the 
latitudes of places given in our former papers, if found neces- 
sary. By fixing on Dunnose, I had also the means of ascertaining 
the distance of the Royal Observatory from the northern or 
southern end of my line, and, consequently, of connecting it 
with the parallels of Dunkirk and Paris. 
Dunnose being fixed on, my subsequent endeavours were 
directed towards carrying on the triangles, as nearly as I pos- 
sibly could, in the direction of its meridian, selecting the stations 
so that their sides might be properly inclined to it, and of suffi- 
cient length. In choosing the station at the northern extremity, 
I was careful to select it as near the meridian of the southern 
one as possible, and likewise in the neighbourhood of some 
open spot of ground, proper for the measurement of a base of 
verification. A station having these advantages, was found near 
Clifton, a small village in the vicinity of Doncaster; and a level 
of sufficient extent for a base, on Misterton Carr, in the northern 
part of Lincolnshire. 
In the composition of this account, I wish to confine myself to 
that part of my operations which relates merely to the matter 
expressed under its title. I am possessed of materials sufficient 
for another Paper; and shall give about thirteen hundred 
triangles, principal and secondary, when next I present art 
account of the Survey to the Society : professing this, I shall 
now say, that in 1800 and 1801, the angles of the triangles con- 
stituting the meridional series were observed ; and that, in the 
latter year, the new base was measured on the abovementioned 
