3. The Peak of Teneriffe in the Canary Islands, which, _in approaching towards it_, Authors agree, may be seen at the Distance of 120 Miles at Sea, if the Weather is clear; (Modern History, Vol. 14th, Page 451;) and, in _returning from it_, is discoverable at the Distance of 150 Miles, according to Glas’s History of the Canaries (Page 234);—has been estimated by Dr. Heberden in Madeira (Guide to the Lakes, Page 187) at 5132 Yards, or 3 Miles within 148 Yards. Glas remarks farther, that in sailing from Teneriffe, the Peak, at the Distance of 150 Miles is very little darker than the _azure_ Sky, on Account of the great Quantity of Vapour intercepted between the Eye and the Mountain: and _not_ because it ceased to be an Object too small for the Sight; or was in Fact, below the Horizon, and only raised by Refraction of the Vapour. With Respect to the Peak of St. George, situated in the Island called _Pico_, one of the Azòres; the Writer of this Account asserts, from the Mouth of an able and experienced Officer in his +Majesty’s+ _Navy_, who, during the last War, cruized some Weeks off those Islands; that the latter has frequently observed the Peak, at the Distance of 120 Miles, and coud then distinguish a _third_ Part of its Height _down_ the Mountain. Section 126, Note (_a_), see also [46] below. 4. Etna is 3877 Yards above the Mediterranean: (according to Brydone’s Tour throu’ Sicily and Malta, Vol. 1. Page 211) or 2 Miles and 357 Yards. 5. Blue Ridge, the highest Mountain in the Island of Jamaica, is, according to Dr. Clark, who measured it in November last, 3080 Yards, or 1 Mile and three Quarters, above the Level of the Ocean. The +distance+ to be +seen+ is considered as terminating the Radius of a Circle, whose Center is the +eye+ of the Observer, on _each_ Mountain. _Height of the Mountains._ +distance+ _to be_ +seen+ _from them in Miles_. _Cotopàzy_ 3 Miles and a Half and } 92 Yards, (for the Process, } 167½ and 405 see Section 52, Note (_a_)). } Yards. _White Mountain_ 3 Miles within } 153¼ and 13 60 Yards. } Yards. _Peak of Teneriffe_ 3 Miles within } 152 within 72 148 Yards. } Yards. _Mount Etna_ 2 Miles and 357 } 132 and 127 Yards. } Yards. _Blue Ridge_ 1 Mile and 3 Quarters. } 117¾ and 30 } Yards. _Balloon_ 1 Mile and half within } 102¼ and 307 33 Yards. } Yards.