Those who do not love trouble, and can afford to have two beds, will find great luxury in rising, when they wake in a hot bed, and going into the cool one. Such shifting of beds, would be of great service to persons ill in a fever; as it refreshes and frequently procures sleep. A very large bed, that will admit a removal so distant from the first situation as to be cool and sweet, may in a degree answer the same end. These are the rules of the art. But though they will generally prove effectual in producing the end intended, there is a case in which the most punctual observance of them will be totally fruitless. This case is, when the person who desires to have pleasant dreams has not taken care to preserve, what is necessary above all things--A GOOD CONSCIENCE. ON THE ART OF SWIMMING. The exercise of swimming is one of the most healthy and agreeable in the world. After having swam for an hour or two in the evening, one sleeps coolly the whole night, even during the most ardent heat of summer. Perhaps the pores being cleansed, the insensible perspiration increases, and occasions this coolness. It is certain that much swimming is the means of stopping a diarrhoea and even of producing a constipation. With respect to those who do not know how to swim, or who are affected with a diarrhoea at the season which does not permit them to use that exercise, a warm bath, by cleansing and purifying the skin, is found very salutary, and often effects a radical cure. I speak from my own experience, frequently repeated, and that of others, to whom I have recommended this. You will not be displeased if I conclude these hasty remarks by informing you, that as the ordinary method of swimming is reduced to the act of rowing with the arms and legs, and is consequently a laborious and fatiguing operation, when the space of water to be crossed is considerable; there is a method in which a swimmer may pass a great distance with much facility, by means of a sail. This discovery I fortunately made by accident, and in the following manner.