33 ° Don J. Rodriguez’s Observations on the 
the azimuths of the exterior sides in his series of triangles by 
means of the greatest elongation of the pole star. 
In the calculations that I have made, I began at Clifton in 
Yorkshire, the northern extremity of the arc, and for this 
purpose the following are the data furnished by Lieut. Col. 
Mudge. 
Latitude of Clifton reduced to the centre of the station 53 0 
27' 36, // 62. 
Azimuth of Gringley, seen from Clifton, and reckoned from 
the north toward the west 256° 1 7' 25". 
Azimuth of Heathersedge, seen from Clifton, and reckoned 
in the same direction 11 8° 8' 8",8i. 
With these data, and the two tables of spherical triangles, 
and the logarithms of their sides expressed in arcs, the inter- 
vals between Clifton and the two stations Gringley and Hea- 
thersedge were found in toises and in seconds of a degree, as 
well as all the corrections to be made on the first azimuths 
increased by 180°, as azimuths of Clifton seen on the horizon 
at these latter places. 
The same process was continued for the following stations 
in succession, all the way to Dunnose in the Isle of Wight, 
which is the southernmost extremity of the series. 
In this manner we have the latitudes and azimuths of each 
station, by means of two or three preceding stations, and con- 
sequently we have a verification of all the calculations that 
have been before made by Lieut. Col. Mudge. 
The results of my calculations are contained in the two fol- 
lowing tables. 
