D E W 
784 I) E W 
which they traverfe at the furface of the earth when that 
air is colder; and, in the laft place, the earth, and all 
bodies which the currents touch, moiftened by the water 
precipitated. Every one muft here perceive the even¬ 
ing and morning dew, with the wind and the cold which 
accompany them ; but a few remarks will complete the 
delcription. We fliull firft obferve, that the defcending 
currents are prolonged until the refiftance of the air 
which they traverfe has entirely deftroyed their motion. 
Befides, we (hall find diredtly under the fun a circular 
fpace very much heated, and which does not. exhibit to 
the inhabitants of that part of the earth the phenomenon 
we are attempting to deferibe. Leaving this part, in 
proportion as the fun appears in a more oblique pofition, 
we (hall arrive at a region of lefs heat, where we (hall 
begin to perceive a wind coining from the quarter of the 
fun, accompanied with a precipitation of water. This 
region forms a ring around the circular fpace before- 
mentioned. In a word, by our removing from the in¬ 
ternal edge of this ring, the wind is found ftronger, the 
cold more fenlible, and the precipitation of water more 
abundant; effects which dill decreafe at a certain dif- 
tance, and ceafe entirely on that part of the earth dia¬ 
metrically oppofite to the fun. Thus, according to the 
hypothefis of the immobility of our globe in regard to 
the fun, there would be on that planet a very extentive 
region continually fubjebt to the phenomenon of morn¬ 
ing and evening dew. Either of thefe expreflions will 
denote the phenomenon, according as the obferver fup- 
pofes liimfelf placed to the eaft or weft of the fun, fince 
the one takes place at the rifing of that luminary, and 
the other at his fetting. 
Let us now return to the real (late of things, and re- 
ftore to the earth its diurnal rotation. In that cafe it 
will fucceffively prefent different parts of its furface to 
the phenomena above deferibed, Thofe who inhabit 
that part where the fun is defcending towards the hori¬ 
zon, w ill foon fee the evening dew appear, accompanied 
with a frelhcning eaft wind; they will fee thefe pheno¬ 
mena increafe more and more until after fun-fet, when 
the effeft will be diminiftied, and at laft ceafe altogether. 
During the night the moifture depofited by the evening 
dew will be evaporated, if the atmofphere be not already 
too much charged with water, and no traces ot it will re¬ 
main. Next morning, at break of day, the phenomenon 
w'ill be renewed on the eaft fide of the obferver, with the 
fame circumftances as the preceding evening, and with 
the fame gradations and the fame effect when the fun is 
(till below the horizon ; but with this very remarkable 
difference, that the effects will be much ftronger than 
thofe of the evening : there will, therefore, be more 
wind, more moifture depofited, and a more fenfible cold. 
The reafon of this is, that in the evening the precipita¬ 
tion of water, the wind, and the cold, which accompany 
it, muft be diminiftied, becaufe the whole takes place in 
the neighbourhood and by the mixture of air, which the 
fun has^heated during the day; while in the morning the 
coolnefs of the night-air leaves or gives to the pheno¬ 
menon a little more effect. We fee alfo that in the two 
temperate zones, wdiere there is a greater difference be¬ 
tween the temperature of fummerand winter, and where 
the length of the days and nights varies a great deal, the 
eftefts of the evening and morning dew will be varied 
and irregular. In fummer, if the air has diifolved more 
water during the day, the diftillation of dew takes place 
in air ftrongly heated, and that of the morning dew in 
air which the fliort duration of the night has cooled only 
to a certain point: in that cafe, the folntion of water is 
,-«onfiderable, and the precipitation of dew leffened. In 
winter, on the other hand, the caufe of the folution is 
lefs, but that of precipitation greater. Local circum¬ 
ftances, and particularly the neighbourhood of water, 
muft alfo have an influence on tfiefe effects. Fine wea¬ 
ther increafes them, and renders them more fenfible, but 
■cloudy weather leffens or annuls them. 
Under the torrid zone a greater equality prevails be- 
tween the days and the nights, fince at the equator they 
confift of tw elve hours each throughout the year. The 
difference of temperature in fummer and winter is lefs ; 
that of the day in comparifon of the night is greater than 
in our latitude, the heat of the day is far more intenfe, 
and the fky is almoft always ferene and unclouded. It 
ought thence to follow’, that the evening and morning 
dew will be more fenfible in fuch a fcorched climate 
than in any other part of the earth. This has in¬ 
deed been obferved by travellers. In Egypt, Turkey,. 
Alla, the Antilles, and Mexico, and on-board lhipst 
which, navigate' between the tropics, evening and morn¬ 
ing dew have been obferved in fuch abundance, that 
bodies expofed to them feemed as wet as if they had 
been drenched with rain. But a confcquence of very 
gieat importance feems deducible from thefe phenomena, 
which is, that' they muft have a great influence on the 
production and duration of the trade-winds ; for the air 
of the torrid zone being excited to motion almoft regu¬ 
larly every day, in two oppofite directions, by forces very 
different in quantity, muft be impelled to affume and to 
preferve a movement in the direction of the ftrongeft, 
which is here the eaft wind, or that which brings with 
it the dew of rite morning. This caufe muft be more 
effectual, as it aCts in the inferior.part of the atmofphere, 
and as, by affeCting the denfeft part of the air, it is more 
capable of eftabliftiing a current in the w’hole mafs. 
Under the frigid zone, where the fun, particularly 
during wfinter, fcarcely rifes above the horizon in the 
courfe of the w hole day, the precipitation of water will 
be confiderable on account of the coidnefs of the climate;. 
the country will be involved in a thick fog, which will, 
be fcarcely difperfed on the approach of fummer; and, 
when it takes place in fummer, it will extend a great' 
way into the temperate zone. Hence, therefore, we ob¬ 
ferve in our own country, during that feafon, confidera¬ 
ble fogs, which are often fo thick as to (ufferonly a faint 
light to penetrate through them even at noon. It would- 
be curious to exhibit here a feries of correct obfervations* 
on the circumftances which accompany the evening and 
morning dew, at different times of the year, and in dif¬ 
ferent countries ; on the hour at which thefe phenomena 
begin, and on the fufpenfion or irregularity by which 
they are affected in different h cal fituations ; and if fuch 
an enquiry could once excite the attention of philofo- 
pliers, the interefting talk would, no doubt, be foon ac=> 
complifhed. 
To DEW, v. a. To wet as with dew ; to moiften ; to- 
bedew : 
Give me thy hand. 
That I may dew it with my mournful tears. Shakefpesre 
DEW-BERRY, f. The fruit of a fpecies of bramble. 
See Rubus. 
Feed him with apricocks and dew-berrics, 
With purple grapes, green figs, and mulberries. Shahefp * 
DEW-BESPANGLED, adj. Befpangled with dew s 
Now the golden morn aloft 
Waves her dew-befpangled wing. Gray„ 
DEW-BESPRENT, part. Sprinkled with dew : 
This evening late, by then the chewing flocks 
Had ta’en their Cupper on the favoury herb 
Of knot-grafs dew.-befp rent. Milton. 
DEW-BORN,/. A diforder in cattle, otherwife called- 
the ho : c, from a violent fwelling of the inteftlnes, which, 
if not fpeedily removed, frequently occafions death. This 
diforder is often induced by turning hungry cattle too 
long at a time into rich moift paftures, or clover, where¬ 
by they blow themfelves, as it is termed by the graziers. 
DEW-BURNING, .adj. The meaning of this com¬ 
pound is doubtful. Perhaps it alludes to the fparkling. 
of dew;. 
He y , 
i 
