PRINTED BY W. BULMER AND CO. CLEVELAND-ROW, ST. JAMES'S,

FOR W. FADEN, GEOGRAPHER TO HIS MAJESTY,

AND TO HIS ROYAL HIGHNESS THE PRINCE OF WALES,

CHARING CROSS.

CONTENTS.

TRIGONOMETRICAL SURVEY, 1797-1799.

INTRODUCTION

Particulars relating to the Operations of the Year 1797

Angles taken in the Year 1797

Particulars relating to the Operations of 1798

page 1

4

11

17

Precautions taken in measuring a Base Line on King's Sedgemoor 19

Angles taken in the Year 1798

Particulars relating to the Operations of 1799

21

25

31

38

46

48

49

Calculation of the Sides of a Set of principal Triangles carried,

on from the Side which joins the Stations on Beacon Hill, near

Amesbury, and Wingreen Hill, near Shaftsbury, towards the

Base of Verification on King's Sedgemoor·

Comparison between the measured and computed Lengths of

the Base

50

35

I

56

Calculation of the Sides of certain principal Triangles carried

on from the Side Bagshot Heath and Highclere, towards the

North
59

Triangles for ascertaining the Situation of the Observatory at

Oxford, and also that of his Grace the Duke of Marlborough,

at Blenheim

b

68

H

Triangles for connecting the Northern Series with that carried

on for the Survey of Essex

page 68

Triangles formed by the Intersections of Churches and other

Objects

72

Calculation of the Distance between Black Down and Dunnose 86

Direction of the Meridian at Black Down

88

Latitude and Longitude of Black Down

91

Calculation of the Distance between Rippin Tor, in Devonshire,

Observations as to the possible Errors in the computed Latitudes

and Longitudes of the Stations, Black Down, Butterton

Hill, and St. Agnes Beacon

Different Methods of computing the Direction of the Meridian

at Black Down

Bearings of the Stations in the Series of 1795 and 1796, from

the Parallels to the Meridians of Black Down, Butterton

Hill, and St. Agnes Beacon; likewise their Distances from ·

those Meridians, and their Perpendiculars

98

103

105

106

Latitudes and Longitudes in the Series of 1795 and 1796

Bearings of the intersected Objects from the Stations in the

Series of 1795 and 1796, from the Parallels to the Meridians

of Black Down, Butterton Hill, and St. Agnes Beacon ; and

likewise their Distances from those Meridians

107

Latitudes and Longitudes of such intersected Objects in the Series

of 1795 and 1796, as have been referred to the Meridians of

Black Down, Butterton Hill, and St. Agnes Beacon page 111

Bearings of the Stations in the Series of 1797 and 1798 from

the Parallels to the Meridians of Black Down, Butterton

Hill, and St. Agnes Beacon; likewise the Distances from,

D

those Meridians

Bearings of the Stations in the Series of 1799 from the Parallels

to the Meridians of Dunnose and Greenwich; and likewise

their Distances from those Meridians

Latitudes and Longitudes of the Stations in the Series of 1797

and 1798

115

116

117

Latitudes and Longitudes of the Stations in the Series of 1799 118

Bearings of the intersected Objects from the Stations in the

Series of 1797 and 1798, from the Parallels to the Meridians

of Black Down, Butterton Hill, and St. Agnes Beacon ; and

likewise their Distances from those Meridians

Bearings of the intersected Objects from the Stations in the Se-

ries of 1799, from the Parallels to the Meridians of Dun-

nose and Greenwich; and likewise their Distances from those

Meridians

119

120

123

Latitudes and Longitudes of Objects intersected in the Years

1797 and 1798

Latitudes and Longitudes of Objects intersected in the Year 1799 124

Latitude and Longitude of St. Nicholas's Island, in Plymouth

Sound

Latitude and Longitude of St. Andrew's Church at Plymouth;

also the Longitude of the Transit Room, at the same Place,

belonging to the late Mr. Thomas Mudge, found by means

of two Timekeepers

Latitude and Longitude of the Lizard Lights

b 2

127

128

131