meafuring Heights with the Barometer . 
SECTION II, 
Experiments on the expanfion of air in the Manometer * 
WITH refpedl to order of time, the manometrical 
experiments were made fubfequently to the chief part of 
the barometrical obfervations, from which alone an ap- 
proximate rule had previoufly been deduced for the mea- 
furement of heights : neverthelefs, in this paper it feemed 
to me belt, that what related to the expanfion oS air in 
one inftrument, fhould immediately fucceed the expan-- 
lion of quickfilver in the other. 
The thermometer made ufe of in thefe experiments 
is above four feet long. Its- fcale extends from - 4 0 to 
+ 224° of Fahrenheit, each degree being more than 
•i;ths of an inch : when the barometer flood at 30 inches, 
its boiling point was fixed in the tin veffel formerly de- 
fcribed. Mr. ramsden’s thermometers generally rife in- 
the fame veffel 21 3°f; and the long thermometer, being 
placed in the veffel he makes ufe of to fix his boiling 
points, rifes only to 2,10°. 
The manometers were of various lengths, from four 
to upwards of eight feet: they confifled of flraight tubes, 
whole 
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