CHAPTERL.CORROBORATING PROOFS OF A DEPRESSION.Sect. 268. Art. 1.THE Author is well informed, that, during an Engagement at Sea;—intenMinutes after the Action has commenced;—tho’ it blew aGalebefore; (that is, tho’ it blewviolently;) the Agitation of the Air, arising from the Explosion of thegreat Guns, and small Arms, woud counteract the Wind, and produce a dead Calm.268. 2. Quere: does not thenew elasticAir, produced from the Nitre,[80]give an instantaneous Compression and Dilatation to theincumbentatmospheric Air, round the Place of Action, while thelighter floguisticated Airpasses throu’ it, raising, and affecting to its highest Limit, thewholeAtmosphere. And does not the Effect of a sudden Calm, suppose the Wind todescend from abovewith a Kind ofsaltatoryMotion, instantly counteracted by thenew elasticAir?—For if the Wind be supposed to blow sideways or horizontally,to any considerable Height abovethe Water, woud not the freshlateralAir glide away, and prevent the Continuance of the Calm?269. When a Squall happens, or only Rain falls; Air willrushfrom all Sides, and fromabove, to supply the Vacancy of the fallen Cloud and Vapour.The Air immediatelyabovemust fall: the lateral Air gravitating towards other Places. HenceCold, and a bright Sky after Rain.270. The Theory of Accumulation may account for the frequentwarmRains in Winter, and during the Night.For the preceding diurnal Accumulation over the Sea, maycirculateduring the Night, at a great Altitude, to restore the Equilibrium and Loss ofcoldLand Air sent by a low or Ground-Wind to Sea, during the Day-Time: particularly, as theAccumulationover the Sea, during Winter, is almostcontinual.271. TheWindwould more frequently be perceived todescendandrebound upwards, (Trials of which might be made by holding an Umbrella, extended at right Angles with its Axis, upright in the Hand;) if the same Opportunity offered, of opposing as great a Surface to it in a perpendicular, as is every Day done, in an horizontal Direction: for in walking, the whole Height of the Body, and half its Surface, is opposed horizontally to the Wind: but the Head only, which is covered, is opposed to the perpendicular Pressure.272. As every Circumstance in the Order of Nature is so admirably contrived that each apparent Inconvenience rectifies itself; inheavyWinds continuing to blow from acoldPoint; the Construction of the Atmosphere is such, that thewarm lightAir from the opposite Points will necessarily rise up and flow over the cold Stratum, and by their Tendency to an Equilibrium, will produce an Airless cold, before thesameWind is exhausted.273. On the one Hand; it is probable, that, as cold Winds are heavy; the Eknèfiai Winds are covered with frequent Waves of the Apogay, or light warm Air rolling over them, frequently from the opposite Points.274. On the other Hand, as theApogayWinds are naturally light and warm, it isimprobablethat they shoud befrequentlycovered with Waves ofcold heavy Air, rolling over them from Eknèfiai Points.It may therefore be reasonably concluded, that the Eknèfiai Winds, when approaching or opposed to the Apogay, shoud be considered asGround Winds, (i. e. Winds blowing next the Surface of the Earth, tho’ they be supposed at the same Time to descend) which receive the Apogay above them: and that the Apogay being warm light andmoist, (which last will have the same Effect, as if they were more elastic;)[81]being also more turbulent, and endued with greater Velocity, press back the Eknèfiai from the Surface of the Earth, and upwards; and at the same Time flow above them.By which means the Eknèfiai partake of their Qualities;—become lesscold, lessheavy, and lessdry.[82]
CHAPTERL.
Sect. 268. Art. 1.THE Author is well informed, that, during an Engagement at Sea;—intenMinutes after the Action has commenced;—tho’ it blew aGalebefore; (that is, tho’ it blewviolently;) the Agitation of the Air, arising from the Explosion of thegreat Guns, and small Arms, woud counteract the Wind, and produce a dead Calm.
268. 2. Quere: does not thenew elasticAir, produced from the Nitre,[80]give an instantaneous Compression and Dilatation to theincumbentatmospheric Air, round the Place of Action, while thelighter floguisticated Airpasses throu’ it, raising, and affecting to its highest Limit, thewholeAtmosphere. And does not the Effect of a sudden Calm, suppose the Wind todescend from abovewith a Kind ofsaltatoryMotion, instantly counteracted by thenew elasticAir?—For if the Wind be supposed to blow sideways or horizontally,to any considerable Height abovethe Water, woud not the freshlateralAir glide away, and prevent the Continuance of the Calm?
269. When a Squall happens, or only Rain falls; Air willrushfrom all Sides, and fromabove, to supply the Vacancy of the fallen Cloud and Vapour.
The Air immediatelyabovemust fall: the lateral Air gravitating towards other Places. HenceCold, and a bright Sky after Rain.
270. The Theory of Accumulation may account for the frequentwarmRains in Winter, and during the Night.
For the preceding diurnal Accumulation over the Sea, maycirculateduring the Night, at a great Altitude, to restore the Equilibrium and Loss ofcoldLand Air sent by a low or Ground-Wind to Sea, during the Day-Time: particularly, as theAccumulationover the Sea, during Winter, is almostcontinual.
271. TheWindwould more frequently be perceived todescendandrebound upwards, (Trials of which might be made by holding an Umbrella, extended at right Angles with its Axis, upright in the Hand;) if the same Opportunity offered, of opposing as great a Surface to it in a perpendicular, as is every Day done, in an horizontal Direction: for in walking, the whole Height of the Body, and half its Surface, is opposed horizontally to the Wind: but the Head only, which is covered, is opposed to the perpendicular Pressure.
272. As every Circumstance in the Order of Nature is so admirably contrived that each apparent Inconvenience rectifies itself; inheavyWinds continuing to blow from acoldPoint; the Construction of the Atmosphere is such, that thewarm lightAir from the opposite Points will necessarily rise up and flow over the cold Stratum, and by their Tendency to an Equilibrium, will produce an Airless cold, before thesameWind is exhausted.
273. On the one Hand; it is probable, that, as cold Winds are heavy; the Eknèfiai Winds are covered with frequent Waves of the Apogay, or light warm Air rolling over them, frequently from the opposite Points.
274. On the other Hand, as theApogayWinds are naturally light and warm, it isimprobablethat they shoud befrequentlycovered with Waves ofcold heavy Air, rolling over them from Eknèfiai Points.
It may therefore be reasonably concluded, that the Eknèfiai Winds, when approaching or opposed to the Apogay, shoud be considered asGround Winds, (i. e. Winds blowing next the Surface of the Earth, tho’ they be supposed at the same Time to descend) which receive the Apogay above them: and that the Apogay being warm light andmoist, (which last will have the same Effect, as if they were more elastic;)[81]being also more turbulent, and endued with greater Velocity, press back the Eknèfiai from the Surface of the Earth, and upwards; and at the same Time flow above them.
By which means the Eknèfiai partake of their Qualities;—become lesscold, lessheavy, and lessdry.[82]