CHAPTERXXXXVII.Difficulties, proposed by Mons. Sauffure stated; and their Solution attempted.Section 259.IT may be observed here, that the two Difficulties proposed by Sauffure, are, in a great Measure, removed; in admitting the Doctrine of mediocèanalDepression, and consequent alternateAccumulation,In a distinct Chapter, treating of the Variation of the Barometer, which he allows has Need of farther Explanation; he asks (Page 308) what Reasons can be assigned, why theEastWinds, which arecold and dry, make the Barometerdescend, in England and Holland: yet, theWestWinds, which aremoist and temperate, make itrise?The East Windshereblow chiefly in Spring.Now it is universally agreed, that the Sea, is sooner heated by the Sun than the Land: and on Account of the marine Acid exhaled,[70]is also less cold,[71]during that Season, in the same Latitude.In Spring, therefore, the great Atlantic or Western Ocean, beinglesscold than England, Holland, and Eastwards; the Air pendent over the most extensive Tract ofdry and cool Landin the World, rushes Westwards to supply the Equilibrium ofwarm lightAir rising upwards, and causing a temporary mediocèanal Accumulation: which (altho’ the specific Gravity of the cold Air is greater) must produce an actual Deficiency in the aggregate Weight of the Atmosphere over England and Holland: consequently the Barometer falls.Again: the West Winds which blow at other Seasons; if, in Winter; are not frequent, except about Noon after frosty Nights which have equalized the Air for the Transmission of vigorous Sunshine: and shoud be looked upon as (what they are really observed to be)lowpartial Sea-Breezes, oreddyCurrents, insinuating themselves near the Surface, and setting Eastwards frequently against the upper and more general Winds; and therefore produce a temporary Accumulation.If, in Summer; the Supply of cool Air to the heated Land, being made not only from theNorthern Ocean, and loftyMediterrànean Mountains; but also from theAtlantic Breezes; the latter, tho’moist and temperate, must also tend towards an Accumulation of the Atmosphere over England and Holland: and therefore the Barometer rises.
CHAPTERXXXXVII.
Difficulties, proposed by Mons. Sauffure stated; and their Solution attempted.
Section 259.IT may be observed here, that the two Difficulties proposed by Sauffure, are, in a great Measure, removed; in admitting the Doctrine of mediocèanalDepression, and consequent alternateAccumulation,
In a distinct Chapter, treating of the Variation of the Barometer, which he allows has Need of farther Explanation; he asks (Page 308) what Reasons can be assigned, why theEastWinds, which arecold and dry, make the Barometerdescend, in England and Holland: yet, theWestWinds, which aremoist and temperate, make itrise?
The East Windshereblow chiefly in Spring.
Now it is universally agreed, that the Sea, is sooner heated by the Sun than the Land: and on Account of the marine Acid exhaled,[70]is also less cold,[71]during that Season, in the same Latitude.
In Spring, therefore, the great Atlantic or Western Ocean, beinglesscold than England, Holland, and Eastwards; the Air pendent over the most extensive Tract ofdry and cool Landin the World, rushes Westwards to supply the Equilibrium ofwarm lightAir rising upwards, and causing a temporary mediocèanal Accumulation: which (altho’ the specific Gravity of the cold Air is greater) must produce an actual Deficiency in the aggregate Weight of the Atmosphere over England and Holland: consequently the Barometer falls.
Again: the West Winds which blow at other Seasons; if, in Winter; are not frequent, except about Noon after frosty Nights which have equalized the Air for the Transmission of vigorous Sunshine: and shoud be looked upon as (what they are really observed to be)lowpartial Sea-Breezes, oreddyCurrents, insinuating themselves near the Surface, and setting Eastwards frequently against the upper and more general Winds; and therefore produce a temporary Accumulation.
If, in Summer; the Supply of cool Air to the heated Land, being made not only from theNorthern Ocean, and loftyMediterrànean Mountains; but also from theAtlantic Breezes; the latter, tho’moist and temperate, must also tend towards an Accumulation of the Atmosphere over England and Holland: and therefore the Barometer rises.