heat, that rarifies and renders it lighter, when it will be pushed away, with its burthen, by cooler, and therefore heavier fresh air; which, for a moment, fupplies its place, and then, being likewife changed, and warmed, gives way to a fucceeding quantity. This is the order of nature, to prevent animals being infected by their own perspiration. He will now be fenfible of the difference between the part exposed to the air, and that which, remaining funk in the bed, denies the air accefs: for this part now manifefts its uneafinefs more dif tinctly by the comparison, and the feat of the uneafinefs is more plainly perceived, than when the whole furface of the body was affected by it.

Here, then, is one great and general cause of unpleafing dreams. For when the body is uneafy, the mind will be disturbed by it, and difagreeable ideas

of various kinds will, in fleep, be the natural confequences. The remedies, preventative, and curative, follow :

1. By eating moderately (as before advised for health's fake) lefs perfpirable matter is produced in a given time; hence the bed-clothes receive it longer before they are saturated; and we may, therefore, fleep longer, before we are made uneafy by their refusing to receive any more.

2. By using thinner and more porous bed-clothes,which will fuffer the perfpirable matter more easily to pass through them, we are lefs incommoded, fuch being longer tolerable.

3. When you are awakened by this uneafiness, and find you cannot easily fleep again, get out of bed, beat up and turn your pillow, fhake the bed-clothes well, with at least twenty fhakes, then throw the bed open, and leave it to cool; in the meanwhile, continuing undreft, walk

E 2

walk about your chamber, till your fkin has had time to discharge its load, which it will do fooner as the air may

be drier and colder. When you begin to feel the cold air unpleasant, then return to your bed; and you will foon fall asleep, and your sleep will be sweet and pleasant. All the scenes prefented to your fancy, will be of the pleafing kind. I am often as agreeably entertained with them, as by the scenery of an opera. If you happen to be too indolent to get out of bed, you may, instead of it, lift up your bed-clothes with one arm and leg, fo as to draw in a good deal of fresh air, and, by letting them fall, force it out again. This, repeated twenty times, will fo clear them of the perfpirable matter they have imbibed, as to permit your fleeping well for fome time afterwards. But this latter method is not equal to the former.

Those

Those who do not love trouble, and can afford to have two beds, will find great luxury in rifing, when they wake in a hot bed, and going into the cool one. Such fhifting of beds would also be of great fervice to perfons ill of a fever, as it refreshes and frequently procures fleep. A very large bed, that will admit a removal fo diftant from the first fituation as to be cool and fweet, may in a degree answer the fame end.

One or two observations more will conclude this little piece. Care must be taken, when you lie down, to difpofe your pillow fo as to fuit your manner of placing your head, and to be perfectly eafy; then place your limbs fo as not to bear inconveniently hard upon one another, as, for inftance, the joints of your ancles for though a bad pofition may at first give but little pain, and be hardly noticed, yet a continuance

will render it lefs tolerable, and the uneafiness may come on while you are afleep, and disturb your imagination.

These are the rules of the art. But though they will generally prove effectual in producing the end intended, there is a cafe in which the moft punctual obfervance of them will be totally fruitlefs. I need not mention the cafe to you, my dear friend: but my account of the art would be imperfect without it. The cafe is, when the person who defires to have pleasant dreams has not taken care to preserve, what is neceffary above all things,

A GOOD CONSCIENCE.

ADVICE