544 The Account of a 



cuts off all view of the southern extremity of Dartmoor from 

 Black Down, the necessary alternative was, the firing of lights 

 on some remote station, communicating with Butterton. Rippin 

 Tor was quickly discovered to be the most proper spot ; and that 

 eminence would, in every point of view, be a most eligible one 

 for a new direction of the meridian, if the hills in the middle of 

 the moor were not considerably higher. It was, therefore, 

 chosen only with a view of being subservient to the purpose of 

 rinding the latitude of Butterton. 



In making observations on the Pole Star, the same precautions 

 were taken to ensure accuracy, as were observed at Dunnose and 

 Beachy Head in the year 1793 ; (see Phil. Trans, for 1795, p. 

 460.) I shall, therefore, not enumerate them, but content 

 myself with observing, that no pains were spared in this per- 

 formance. 



From Black Down, the party removed to Butterton ; at which 

 place but few observations were made, the weather being either 

 tempestuous or hazy, during the greatest part of the time we 

 were at that station : they were, however, made under favour- 

 able circumstances, in other respects, and are therefore likely 

 to afford accurate results. 



As in the case of Rippin Tor, with respect to Black Down, so 

 Hensbarrow, in Cornwall, was selected as the spot for connect- 

 ing St. Agnes Beacon with the station on Butterton; for these 

 latter are not visible from each other, the high land about St. 

 Austle, on the northern part of which is situated Hens or Hengist 

 barrow, being higher and intermediate. The staff to which the 

 lights and star were referred, was placed on a hill called Hem- 

 merdon Ball, a secondary station in the series of 1 795. 



On the ist of May, the party proceeded to St. Agnes Beacon; at 



