The Ordnance Survey. 35 
I write this letter, not to expose error, but to prevent 
misconception. Scientific controversy is, it is to be hoped, 
agreeable to no one; it is most disagreeable to me, and I have, 
it seems, become entangled in it by seeking tc avoid it, but I 
will not be misconceived by the public; had I not been men- 
tioned (and it appears to me quite unnecessarily mentioned) 
I should have been much better pleased to have remained 
silent. Professor Daniell has (probably for good reasons) 
avoided my name when making a copious use of my results * ; 
I wish he had carried out this principle, and not introduced 
my name into a controversy with which I have nothing at all 
to do. I remain, my dear Sir, yours very truly, 
Swansea, Dec. 1842. W. R. Grove. 
VII. The Ordnance Survey. 
T is with no small satisfaction that we announce to our 
astronomical friends the appearance of a new volume of 
the Trigonometrical Survey. During the long interval of 
thirty-one years which has elapsed since the publication of the 
last volume in 1811, the sole fruits of this important and costly 
operation have been a series of county maps—admirably ex- 
ecuted, we admit, and of the highest value in reference to the 
topography of the country—still in course of preparation and 
publication. No observations or results connected with geo- 
desy have been officially communicated; and indeed if we 
except the few meagre accounts which have been occasionally 
furnished to Parliament, the public, generally, has had no 
information respecting the state and progress of the work. 
The appearance of the present volume is therefore highly 
gratifying, not only on account of the observations it contains, 
but also by reason of the promise held out that the mass of 
valuable results which has so long been accumulating will at 
length be available for the better determination of the dimen- 
sions and figure of the earth. After all, it may ultimately be 
found that the delay which has taken place in completing the 
meridional arc is not greatly to be regretted. Within the last 
twenty years the theory of computing geodetical observations 
has received considerable improvements in the hands of Gauss 
and Bessel, and advantage will no doubt be taken of the new 
methods to render the results as perfect as possible. ‘The in- 
struments which have been used in the Ordnance Survey, 
both for the astronomical and geodetical observations, have 
been far superior to those which were employed in the cele- 
brated operation for determining the French are of meridian, 
* See Phil. Trans. 1842, p. 271 et passim. 
D2 
