9^ Mtfcettanea Curiofa. 



2» Why in fercne gcol fettled weather the Mer- 

 cury is generally high? To this I Anfwer, That 

 the greater height of the Barometer, is occafion'd 

 by two contrary Winds blowing towards the 

 place of Obfervation, whereby the Air of other 

 places is brought thither and accumulated ; fo 

 that the incumbent Cylinder of Air being en- 

 creasM both in height and weight, the Mercury 

 prefs'd thereby muft needs rife and ftand high, 

 as long as the Winds continue fo to blow ; and 

 then the Air being fpecifically heavier, the Vapours 

 are better kept lufpended, fo that they have no 

 inclination to Precipitate and fall down in Drops, 

 which is the reafon of the ierene good Weather, 

 which attends the greater heights of the Mer- 

 cury. 



3. Why upon very great Winds or Storms, tho 

 accompanied with no J{ain, the Mercury finks low- 

 eft of all, with relation to the Point of the 'Compafs 

 upon which the Wind blows ? This is caus"d by 

 the very rapid Motion of the Air in thefe Storms, 

 for the Tract or Region of the Earths Surface, 

 wherein thefe Winds rage, not extending all 

 round the Globe, that ftagnant Air which is 

 left behind, as likewife that on the fides, can- 

 not come in fo fall: as to fupply the Evacuation 

 made by fo fwift a Current ; fo that the Air 

 muft neceffarily be attenuated, when and where 

 the faid Winds continue to blow, and that 

 more or lefs, according to their Violence ; add 

 to which, that the Horizontal Motion of the 

 Air being fo quick as it is, may in all probabi- 

 lity take off fbme part of the perpendicular 

 preffure thereof ; and the great Agitation of 

 its Particles, is the Reafon why the Vapours 

 are diffipated, and do not condenfe into Drops, 



