636 Meteorological Obfervations. 
Remarks on the Barometer. . 
III. Taking the generally adopted ideas to be 
juft, viz. that when the quickfilver is high (or 
towards thirty inches) with the wind to the 
north of the weft and. S. E. points, it is an 
indication of fair weather (provided it has not 
rifen too fuddenly) ; and that when the quick- 
filver is low (or towards twenty - eight 
inches,) with the wind in the S. or’S. W. 
points, it is an indication of rain; my expec- 
tations of the more immediate future fiate of the 
weather, in any fituation of the quickfilver, are 
taken from the appearance which the furface 
of the quickfilver in the tube exhibits. If this 
be convex (i. e. with a roundifh, fomewhat 
globular appearance) it is a certain indication 
that the quickfilver is either rifing, or that. it 
keeps a propenfity to be ftationary, in oppofition 
toa falling flate. On the contrary, when the 
furface of the quickfilver exhibits a concave, 
ragged, or flat appearance, it fhows that it is 
dropping, or that it has no tendency to rife. 
The reafon of thefe appearances feems to be, 
that when the quickfilver is rifing in the tube, 
the particles neareft the fides are attracted by 
the glafs, and retarded in their progrefs upwards, 
whilft that part of the quickfilver which is 
towards the center of the tube, being out of 
the influence of this attraction, rifes with more 
freedom, 
