322 Mr Galbraitli's Barometric Measurements of Heights. 



Height by the formula above, 18307 



By the tables of Biot, . . 12334, 



Oltmanns, . 12274 



Baily 12278 



By a set of tables computed by myself, including dew points, lati- 

 tude, &c. and adopting Dalton's hypothesis of the expansion of air, 12357 

 By that of an equable expansion adopted by Gay Lussac, 



Dulong, &c. ' . • . 12463 



Mean of the whole, . . 12335.5 



Whence it appears that Biot's tables and my tables and formula agree in giv- 

 ing the same height nearly, while those of Oltmanns, Baily, and mine, adapt- 

 ed to an equable expansion of air, differ somewhat considerably, the former in 

 defect, and the last in excess. I suspect that the barometric observations, 

 and tlie trigonometrical operations, that have been made to determine this 

 height, have not been sufficiently numerous to sliow which of all these me- 

 thods is the more accurate. 



A few determinations of the height of this Peak may be stated here, vvhich 

 appear most worthy of confidence, as many of them seem to be performed in 

 such a manner, that the results can be only tolerable approximations. 



Barometrical Measurements of the Height of the Peak calculated from the Formula 

 of Laplace. 



Father Feuille, in 1724, 12957 feet. 



M. Borda, in 177C, 12646 



MM. Lamanon and Monges, in 1785, .... 12179 



M. Cordier, in 1803, 12284 



Professor Smith, in 1815, 12188 



Baron Von Buch, calculated by Dr Savinon, . . . 12131 



Mean of the whole, . 12397.5 



Tliis result does not differ considerably from the last ; but the degree of 

 confidence to be placed in a mean from wliich the extremes differ so much as 

 2C6 feet, cannot be very great. 



From the observations of Martini^re, who accompanied Lapeyrouse, I 

 found by a mean of my tables 12345 feet. 



Several geometrical measurements of this Peak have been made, but those 

 taken under sail cannot be much depended, on, nor can several of the more 

 earl V, from bases frequently too short that have been taken on shore. The one 

 most to be trusted, perhaps, was that by Borda in 177^, which gave 12188 

 feet, about 150 feet less than any of those means, and proves how difficult it 

 is to arrive at the truth, or to render the result of one observation strictly 

 conformable to that of another, except by a process of cooking, as Mr Babbage 

 appropriately terms such admirably consistent results. 



Example II. Required the height of Carnethy, one of the highest of the 

 Pentland hills, from the following observations, being the means derived 

 from a series continued for several hours, on the 2d of August 1828, on the 



