of them can be measured with perfect accuracy, together with the chances of the amplitudes being in some small degree, either in excess or defect, we may consider the result as sufficiently consistent and satisfactory, and take 60823 fathoms in latitude 52° 34', or the centre of England, as the length of one degree.

SECTION SIXTH.

ART. 1. Latitudes and Longitudes of Five principal Stations.

At page 308 of the first volume of the Trigonometrical Survey, the latitude of Dunnose is stated to be 50° 37' 7" 3, and its longitude 1° 11′ 36′′, west from the meridian of Greenwich. The former is derived from the supposition of 50° 44′ 23′′7 being the latitude of Beachy Head, and the latter from 15° 11′ 9′′ being the longitude eastward of that station. On this occasion it is proper to remark that, the difference in longitude as well as latitude of those stations, was determined from observations made on the pole star.

The arc in the heavens corresponding to its terrestrial subtence between Dunnose and Greenwich, is o° 51' 31",39. See the account of the measurement of an arc of the meridian, page 107. Taking the latitude of Greenwich as 51° 28′ 40′′, we get 50° 37' 8",61 for the corrected latitude of the first mentioned station, differing 1",3 from the previous deduction.

The arc between Dunnose and Clifton Beacon, in Yorkshire, see the account of the former measurement, page 107, is 2° 50′ 23",38; therefore 50° 37′ 8′′,61+2° 50′ 23′′,38=53° 27′ 31′′,99 is the latitude of Clifton.

At page 57 of the same account, the bearings of the stations. connecting Clifton Beacon and Dunnose, from the parallels to the meridian of the former, are given, and these bearings, which it will be necessary to repeat on another occasion, give 4917 feet for the distance of Dunnose from the meridian of Clifton. This

distance, using 61182 fathoms for the length of the degree perpendicular to the meridian in latitude 50° 41′, combined with the latitude of Dunnose as just found, gives 1' 16",5 the longitude of Clifton west from Dunnose. Therefore 1° 11′ 36′′,+1′ 16′′,5 1° 12′52′′,5, is the longitude of Clifton west from the meridian of Greenwich, 1° 11′ 36" being the longitude of Dunnose.

The amplitude of the celestial arc, corresponding to the difference of latitude between Dunnose and Burleigh Moor, as shewn in a previous article, is 3° 57′ 13,"1. This, added to the latitude of Dunnose, gives 54° 34′ 21′′,7 for that of Burleigh Moor.

In the former article, the distance from the parallel at Dunnose to the meridian of Burleigh Moor, is 36778 feet. This, calculating with the latitude of Dunnose, and 61182 fathoms for the length of the degree perpendicular to the meridian, gives 9' 31",6 for the longitude of Burleigh Moor east from Dunnose. Therefore 1° 11′ 36′′—9′ 31′′,6=1° 2′ 4′′,4, is the longitude of that station west from Greenwich.

The latitude of Dunnose is 50° 37' 8,61. The difference between the parallels of that station and Blackdown in Dorsetshire, is 4' 6"5; (see the second volume, page 90), therefore 50° 37′ 8′′,6+4′ 6′′5=50°41′ 15′′,11 is the latitude of Blackdown, which in the account of 1801, is stated from calculation to be 50° 41′ 13′′8. The subtense of the arc, contained by the parallels of Dunnose and Delamere Forest, has been shewn in a foregoing article, to be 2° 36′ 12′′,2, therefore 50° 37' 8",6+2° 36' 12′2=53° 13′ 20′′,8 is the latitude of the station on Delamere Forest.

The distance of the parallel at Black Down, from the meridian of Delamere Forest, is 31546,3 feet. This has been shewn in a former page. Taking 61182 fathoms for the length of the degree

perpendicular to the meridian, and using 50° 41′ 15′′ for the lati tude of Black Down, we get 8' 8",4 for the longitude of Delamere Forest west from Black Down. The longitude of Black Down is 2° 32′ 22′′,4, see the second volume, page 91. Therefore 2° 32′ 22′′,4+8′ 8′′4=2° 40′ 30′′,8, is the longitude of the station on Delamere Forest west from the meridian of Greenwich.

In a subsequent article, specifying the bearing and distances of the several stations from their respective meridians and perpendiculars, it will be shewn that Moel Rhyddlad, in Anglesea, is 406629,7 feet from the meridian of Delamere Forest, and 62475,3 feet north from the perpendicular at that station. These distances converted into their correspondent arcs, and used as data, give 53° 22′ 45′′,38 for the latitude, and 1° 51′ 21,"1 for the longitude west from Moel Rhy dlad. The longitude of Delamere Forest is 2° 40′ 30′′,8. Therefore 2° 40′ 30′′.8+1° 51′ 21′′,1=4° 31′ 51,"9 is the longitude of Moel Rhyddlad west from the meridian of Greenwich.

The latitudes and longitudes of these important stations, brought into one point of view, will be as follow.

ART. II. Bearings and Distances of the several Stations from the Parallels and Perpendiculars to their respective Meridians.

The Bearings of the Stations Lilley hoe and Lidlington, and Bow Brickhill and Lilleyhoe, from the parallels to the meridian of Greenwich, and their distances from the meridian and its perpendicular, as given at page 116, in the second volume, are the data on which the above results are founded, combined with the angles and sides of the proper Triangles.