23;8 PHILOSOPHICAL TRANSACTIONS. [aNNO 1777- 



N" I . Heights in and near London. Height in feet, 



St. Paul's Church-yard, north side, and iron gallery over the dome Jgl 



Top of" Paul's stairs, and the said gallery 324. 



Top of Scotland-yard wharf, and the dining-room of tlie Spaniard on Hampstead-heath .... 422 



Great Pulteney-street, and the said dining room 352 



Pagoda in Kew gardens Il6'^ 



Gun wharf in Woolwich Warren, and uppermost story of Shooter s-hill inn 444. 



N" 2. Near Taybridge in Perthshire. 

 Station at the east gate of Castle Menzie's gardens near the village of Weem, and top of 



Weem Craig 700| 



The said station, and top of Bolfrack's Cairn 1076^ 



The said station, and top of Dull Craig l'-44| 



The said station, and top of Knock Fade 1 30"4| 



The said station, and that at tlie rivulet of Glenmore, below the south observatory on Schihallien 1279| 



The said station, and south observatory 2098 



The said station, and western summit of Schihallien 3281 



Station at the rivulet of Glenmore, antl the south observatory 8 1 8| 



N° 3. Near Lanark. 



Level of the Clyde at I anark-bridge, and station in the garden at Lanark 3(i2j 



Ditto level, and top of Stonebyre-hill , 654 



Robin Hood's well, before Carmichael-house, and top of Tinto, 4 feet below the summit of 



tlieCairu i6i'2l 



Ditto well, and west end ci' Carraichael-hill 45 1| 



N° 4. Near Edinburgh. 



LeiOi pier-head, and top of tlie Calton-hill 344 



Leith pier, and summit of Arthur's Seat 803 



Leitli pier, and Kirk-yetton Cairn, on the east end of the Pentland- hills 1544 



Calton-hill, and ditto Cairn 1200 



Level of Hawk-hill study, and top of Arthur's Seat 702| 



Hawk-hill observatory, and bottom of the little rock on Arthur's Seat, 7i feet below the summit 684 



Hawk-hill garden door, and ditto little rock 730| 



N" 5. Near Linhouse. 



LinJiouse, and East Cairn-hill, 5 feet below tlie summit 1 1 76 J 



Ditto, 18 feet below the top 1 165| 



Linhouse, and West Cairn-hill, 1 I feet below tlie top 1178| 



Ditto, and Corstown-hiU, 4 feet below tlie top 386| 



Corstown-hill, and West Cairn-hill 792 



Ditto, and East Cairn-hiU 776J 



N° 6. Near Carnarvon in Nortli Wales. 



Carnarvon Quay, and Snowdon Peak 3555 



Ditto, and summit of Moel Eilio 2371 



To enter into a minute detail of the geometrical operations, by which the 

 whole of these vertical heights were determined, would be extremely tedious and 

 uninteresting. That some idea may however be formed of the degree of accu-' 

 racy with which they were ascertained, it will be sufficient to observe, that the 

 requisite angles were taken with an astronomical quadrant of a foot radius, made 

 by Sisson, and curiously adapted for the measurement of horizontal or base 

 angles; which, as well as those of the vertical kind, might always be thus deter- 

 mined to within 10 seconds of the truth. The bases were measured with care; 

 and, in order to ascertain the distances, the 3 angles of each triangle were, as 

 often as possible, actually observed with the quadrant. That the variation of the 



