Evenhig and Morning Dew. 1 1 J 



and this current would be incrcafed by the vacuum formed 

 at thofe places where the air, fufficiendy elevated and cooled, 

 precipitated its fuperabundant water. 



We need only to modify this image a very little to make 

 it correfpond with the contour of our globe. The conical 

 furface will be converted into a fpherical fegment inclofing- 

 the enlightened portion of the earth, and according to the 

 curvature of which, the before-mentioned currents will be 

 eftabliflied. This curvature will be feen in the annexed 

 figure, (Plate III.) which reprefents the globe of the earth 

 placed in the centre of a circular ftratum fuppofed to be oc- 

 cupied by the atmofphere. The circumference of the earth 

 contains tvventv-four divifions, from which arife as manv 

 perpendiculars to its furface, in order to give an idea of the 

 variations of the phenomena from hour tohour. The fun, 

 placed towards S, in the prolongation of the line TS, is fup- 

 pofed to have his whole mafs united in his centre, which 

 can do no hurt to the objecl which we have here in view. 

 In the laft place, the curve ABC, traced out at random be- 

 caufe its law is unknown, will be fufficient to give an idea of 

 the eflefts which we are defirous of illufirating. 



Such, then, will be the refult of the circumliances fuppofed : 

 Water diflolved by the inferior air in the part expoled to the 

 fun; an afcending movement of the air in that part; de- 

 fcending currents diverging from all fides, and prolonging 

 themfelves over the earth ; thefe currents carrying with them 

 water which they have taken from the heated columns that 

 rife, and which are forced off in a lateral diredlion ; this 

 water thus carried away precipitated, either becaufe the air, 

 coming from the upper regions, is too cold to keep it dif- 

 folved ; or on account of the diminution of prefTure arifing 

 from the weight of the columns being lefs in proportion to 

 their diftance from that immediately under the fun; or in 

 confequence of the mixture of currents with the atmofpheric 

 air, which they traverfe at the furface of the earth when that 

 air is colder; and, in the lad place, the earth, and all bodies 

 which the currents touch, moidened by the water precipi- 

 tated. 



pvery oi)c mufi. here perceive the evening and morning 



dew 



