Mr. Farey’s Remarks on the Trigonometrical Survey. 55 
and repeated, at so many others of the British Stations, as to be 
able to institute rigid calculations, of the lengths of degrees of 
Latitude, ou two or three other Meridians, besides that already 
calculated, which passes through Dunnose in the Isle of Wight; 
and also degrees of Longitude, (or else of great circles perpen- 
dicular to some particular meridian) in several different Latitudes : 
in order, that by the consistency and agreement or otherwise, 
amongst the resuits, with the known fact of the Earth nearly ap- 
proaching in figure to an Ellipsoid slightly flattened at the Poles, 
it may be seen, and duly appreciated, what degree of dependence 
can be placed on the methods of observations and calculations, 
which hitherto have been adopted or recommended. 
In particular I am anxious, that the District around and to the 
northward of Arbury Hill, wherein Capt. Kater has concluded, 
that a mass of the Stratification of great comparative specific 
Gravity, must be situated, at no great depth below the surface, 
should be surrounded and crossed by several lines or degrees of 
latitude and of longitude, and by those also of oblique Arcs or 
Rhombs, between the several Stations surrounding the district 
under investigation: from which, and the proposed minute Stra- 
tigraphical Surveys, to try the practicability, of consistently de- 
ducing the magnitude, shape, position and specific Gravity of 
the supposed heavy or deflecting Mass, which is assumed to have 
occasioned such a deflection of the plumb-line at Ardury Hill 
Station, as to have presented the anomaly, of degrees of the Me- 
ridian, increasing in length, in the contrary direction to those of 
the Ellipsoid, above alluded to: and whether or not, a mass of 
Granite, the top of which presents itself at Mount Sorrel, Grooby, 
and other places* in and near to the south part of Charnwood 
Forest, is sufficient to account wholly, or in considerable part, for 
the deflection alluded to. 
Until the facts as to our own country shall have been settled 
beyond dispute or doubt ; or at least, until the attempt shall se- 
riously have been made, to explain or remove the Arbury-Hill 
anomaly in the lengths of meridional Degrees, it would, I submit 
to your Readers, be premature, and likely to perpetuate rather 
than to remove errors, if the Observations, merely as hitherto 
conducted, and without going more deeply into the subject, were 
extended to the other countries of Europe, with the view, as the 
Committee appear to propose, of thereby coming to definitive 
* See my Derbyshire Report, vol.i. p. 151: observing, that this was 
written, before the unconformableness of numerous local parts of the English 
stratification, had been made out, or the effects of such unconformableness 
sufficiently considered by myself or any other Writer. See. P.M. vol. xiii. 
p- 330 Note, vol. xlv. p. 169, &e, 
coll- 
