( 1095 ) 
Mercurial Particles coming fnto contact with the Glafs, 
than what recede from the contadt of one another, it 
is no Wonder, that the Attraction of tlie Glafs prevails, 
and cautes the Globule to adhere to it For the num- 
ber of Mercurial Particles which lofe their contaCl with 
the other Mercury, is no more than what makes up 
the difference of Surface, which arifes from changing 
the figure of the Drop: whereas the Particles, W’hich 
by this means come to adhere to the Glafs, are all 
thofe that conftitute the plane Surface, in which the 
Globule touches it. 
Which Confideration ought likewife to be apply’d 
to the Sufpenfion of Quickfilver in Glafs Tubes, cither 
at extraordinary heights in the open Air, or at lefTer 
heights in a f^aerntm, as above mention'd. For the top 
of the Tube being Spherical, or nearly fo, it will be 
found, that the contaCf of the Mercury with the extre- 
mity of the Tube, is to the contad with other Mercu- 
ry, which would be gain’d by its leaving the Top of 
the Tube and defeending a very fmall fpace, in zRath 
infinitely great ; and confequently that the contaCl of 
the Mercury with the top- of the Tube is one caufc 
of its Sufpenfion. 
Coroll ifi. From this Propofition it appears, that in a 
Barometer made with a narrow Tube, the Quickfilver 
will never (land at fb great a height as in a wider. 
Which accounts for the I hxnomenon fo often mention’d 
in the Yearly Hiftory of the Royal Academy of Scien- 
ces at ?Arh^ by Monf. De Ia Hhc \ that in the Barome- 
ter, which he confiantly made ule of for his annual Ob- 
i'ervations, the Quickfilver did nor rife lo high, as in 
another he kept by him, by about three Lines and a 
half, which is near a third of an Inch our Mealure : 
For he tells us, that the Tube of his Barometer is very 
fmall*^ So that there is no need to have recourfe to any 
pc.CllS 
