in order to afcertain the height of Mountains . 515 
But to proceed. The inftruments. I made ufe of in 
thefe operations were, two of ramsden’s barometers^; 
three or four thermometers detached from the barome- 
ters, w'hofe boiling and freezing points I had examined 
myfelf; an equatorial inftrument, the circles of which 
were about feven inches diameter, made by ramsden; 
a fifty-feet iteel meafuring chain; and three three-feet 
rods, two of deal and one of brafs,, in order to examine 
and correct the chain, thefe latter made by baradelle 
at Paris. Befides thefe I took with me a little bell-tent, 
which I found of great ufe, as it defended me from the 
wind and fun.; and I may remark, that the obfervations 
of the uppermoft barometer were made in the tent. 
My firft feries of obfervations I propofed to be on 
Mont Saleve <b \ one of the Alps, fituated about two 
( a ) It may not be improper to remark, that the fpecific gravity of the quick- 
lilver of thefe barometers with 68° of heat was 13,61; the diameter of the 
bore of the tube 0,20 inch; and that of the refervoir 1,5 inch. 
(b) Mont Saleve-extends near nine miles -in length.; is not quite 3300 feet 
in height above the Lake. That fide of it which is next Geneva is for the 
1110ft part a barren rock, the north-eaft end of it being almoft a perpendicular 
precipice; the other fide of the mountain is lefs rude, of a more gentle accli- 
vity, covered with trees, fhrubs, and herbage, as is alfo the top, where is fome 
of the finefl paflure in the world. It is inhabited only by a few fhepherds, who 
pafs the fummer months here with their cattle, in little miferable huts or 
'barns-; the remaining part of the year, .viz. for about four or five months, it 
is covered with fnow. This -mountain contains chiefly a calcareous ftone ; 
and there is reafon to believe that there is an iron ore in it, at leaft in fome 
parts of it, as a piece Mr. de luc, the brother, .picked up near the fouth-wefl 
end, I found, fenfibly affe&ed the magnet. 
X x x a 
leagues 
