Bathing is an undescribed luxury. To feel the wind blow on your body, the water flow on you and lave you, is a rare physical enjoyment this hot day. The water is remarkably warm here, especially in the shallows,—warm to the hand, like that which has stood long in a kettle over a fire. The pond water being so warm made the water of the brook feel very cold; and this kept close on the bottom of the pond for a good many rods about the mouth of the brook, as I could feel with my feet; and when I thrust my arm down where it was only two feet deep, my arm was in the warm water of the pond, but my hand in the cold water of the brook.

Thoreau, Henry David. The Journal of Henry David Thoreau, 1837-1861