f 545 ) 
with the Rules laid down by M. Mariotte * in or- 
der to which, and conform to the faid Rules, he cal- 
culated two Tables, one Ihewing the Height of the At- 
mofphere ,as it anfwers to every Line of Mercury in 
the Barometer, the other determining the Height of the 
Atmofphere above the Level of the Sea at given Alti- 
tudes of Mercury. But having afterwards, upon Com- 
panion, found that the Obfervations made in 1703, did 
not in the Main agree with the Rules of M. Mariotte , 
and that the Heights of Places, as they appeared by 
thofe Obfervations, exceeded, generally fpeaking, the 
Numbers refulting from the Tables made by him ac- 
cording to the faid Rules, he thought it neceffary to 
calculate two new ones, wherein indeed the Refults 
are conliderably greater than in the Tables framed ac- 
cording to the Rules of M. Mariotte ; infomuch, that 
for Inftance, a Place, where the Mercury falls to zz 
Inches, rifes above the Level of the Sea, according to 
Mariotte , 852, Toifes, or ^nzFaris Feet} and, ac- 
cording to Gajfini) n^B loifes, or 6948 Feet, which, 
makes a Difference of 1836 Faris Feet, or 306 Toifes. 
Dr. T>efaguliers, 'm his Diilertation concerning the Fi- 
gure of the Earth f, hath already (hewn how far the 
Obfervations made by the Gentlemen, that drew the 
Meridian acrofs the Kingdom of France , differ from 
each other j infomuch, that there are not two in nine, 
where the Number of Toifes, faid to correfpond to the 
Heights of the Barometer, agree together- and that con- 
fequently the Heights of Mountains, as determined by 
thefe Obfervations, are little to be depended on. 
* Mcmoires de 1 ’ Acad. Royale, 1705. pag. 6 1. & f eq , + Phil. TrariC 
386. pag. 211. 
*• . 
* 
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