Mifcellanea Citrio/a. 379 



and therefore tho' regulaily the Mercury would 

 always fall at the New and Full Moon, thofe 

 other Caufes may be ftrong enough, even to 

 Taife it at thofe Seafbns; in as much as two con- 

 trary Winds, for inftance, blowing towards the 

 Place of Obfervation, may accumulate the Air 

 there, fo as to increafe both the height and weight 

 of the incumbent Cylinder ; in like manner, the 

 Direction of twoWindsmay befach,as meeting at 

 certain Angle they may keep the Gravity of the 

 Air in the middle place unaltered ; and a Thou- 

 (and fuch Varieties there may be, by which the 

 Regularity of Appearances of this nature may be 

 hindered. Now the other Springs, from which 

 fuch Changes in the Air may arife, are thefe. 



I. Elaftic Vapours forc'd from the Bowels of 

 the Earth, by Subterraneous Heats, and con- 

 denfed by whatever caufe in the Atmofphere. 



a. A mixture of Effluvia of different quali- 

 ties in the Air, may by Rarefactions, Fermen- 

 tations, produce Winds and other Effects 

 like thole refulting from the Combination of 

 fome Chymical Liquors ; and that fuch things 

 happen, we are affured from the Nature of Thun- 

 der, Lightning, and Meteors. 



3 .From the Eruptions of Vulcanoes and Earth- 

 quakes in diftant Places, Winds may be propa- 

 gated to remoter Countries. 



4. The divided or United Forces of the other 

 Plasets and of Comets, may varioufly difturb the 

 influence of the Sun and Moon, ($c. We know 

 that there happen violent Tempefts in the upper 

 Regions of the Air, while we below enjoy a 

 Calm j and how many Ridges of Mountains there 

 are on our Globe, which interrupt and check the 

 Propagation of the Winds ; fo that it is no won- 

 der 



