1 2 -8 Gen. Roy’s Account of 
the inftruraent was brought back to town, in the neighbour- 
hood of which it was employed for three days for the follow- 
ing purpofe, 
^ In 1787, when at the Rations of Hundred Acres, Norwood, 
Greenwich, and Snooter s Hul, we had only been able to de- 
termine, in a fatisfaftory manner, two points within the limits 
of the Capital, namely, St. Paul’s Church and Argyll Street, 
the laft by means of the white lights. Bearings of feme 
others, it is tine, were QDtained ; but, in order that thefe 
might be intei fedted in the bed manner, it became neceflary 
to place the inftrument at one or more Rations to the north- 
ward of the town. 
With the view, therefore, of laying the foundation hereafter 
foi a much more accurate plan of London than could poftibly 
be obtained in any other way, the inftrument was placed, firft, 
at Hornfey Hill, to the eaftward of Highgate ; and, fecondly,’ 
on Primiofe Hill, between London and Hampftead. 
Althougn the weather was rather unfavourable at the time 
of making the obfervations from thefe two new ftations ; and 
that the fmoke conftantly hanging over the town in the latter 
feafon impeded us greatly; neverthelefs, the former bearings 
were interfered, and the fituations of a confiderable number 
or remarkable fteeples within London and its environs, were 
accurately determined, as will more fully appear in treating of 
the fecondary triangles. 
Having thus briefly ftiewn the order with regard to time in 
which the recent operation, through its various fteps, was 
progreffively carried on and compleated, it is proper that I 
fhould mention, that Mr. Dalby, who had been recom- 
mended as an affiftant, has acquitted himfelf throughout the 
wnole perfeflly to my fatisfadlion, as a diligent and accurate 
5 obferver, 
