Thoreau's Journal: 01-Aug-1856
Since July 30th, inclusive, we have had perfect dog-days without interruption. The earth has suddenly [become] invested with a thick musty mist. The sky has become a mere fungus. A thick blue musty veil of mist is drawn before the sun. The sun has not been visible, except for a moment or two once or twice a day, all this time, nor the stars by night. Moisture reigns. You cannot dry a napkin at the window, nor press flowers without their mildewing. You imbibe so much moisture from the atmosphere that you are not so thirsty, nor is bathing so grateful as a week ago. The burning heat is tempered, but as you lose sight of the sky and imbibe the musty, misty air, you exist as a vegetable, a fungus.