Dr. Fothergill on the practice of sleeprng on the wet ground. 207 
have unguardedly ventured to persuade the public, that the ill effects 
3 imputed to sleeping in damp linen are merely imaginary ; nay further, 
that the sprinkling of the sheets with cold water on going to bed is 
wonderfully salutary and refreshing, particularly to the weary travel- 
ler, exhausted with fatigue. Should our travelling invalids be so sil- 
ly as to be misled by sucha doctrine, or so imprudent as to hazard 
the experiment, they would soon feel cause to be convinced of their 
folly, and to lament their credulity. 
It is therefore not without ¢ and regret, that one sces so 
many inconsiderate people, under the above ——s babe! pros- 
trate on the damp ground, often sleeping for hours ; sometimes 
after rain, and when innumerable Se arcs tre Widtate 6a the: sass ; ; 
a practice too common, but which can never be sufficiently reprobat- 
ed.* It has been discovered by experiments, that even in the driest 
seasons, a square foot of earth exhales an almost incredible quantity 
of watery moisture ; that the evaporation increases in proportion to 
the heat of the atmosphere, and that, in ESE tothe rapichty, of 
evaporation, cold is generated. This process may be easily increased 
to a degree sufficient to convert water into ice, as an article of luxury, 
even in the hottest climates, a as is well known in the East and West 
Indies. | 
In the temperate ‘climate of Great Britain in a dry season, Dr. 
Watson discovered by experiment, that an acre of grass plat, clean 
mowed, yielded by evaporation after the rate of 1600 gallons per day, 
and after rain considerably more. The quantity of aqueous evapo- 
rations, ceteris paribus, is in direct proporti@f to the surface exposed, 
the heat of the climate, and the dryness of the atmosphere. Hence 
* For example, in the State House garden. of Philadetphia, although n nomerous 
benches are always ready to accommodate company with seats, a ; 
