in Thoreau’s Journal:

That first frost on the 17th was the first stroke of winter aiming at the scalp of summer. Like a stealthy and insidious aboriginal enemy, it made its assault just before daylight in some deep and far-away hollow and then silently withdrew. Few have seen the drooping plants, but the news of this stroke circulates rapidly through the village. Men communicate it with a tone of warning. The foe is gone by sunrise, but some fearful neighbors who have visited their potato and cranberry patches report this stroke. The implacable and irresistible foe to all this tender greenness is not far off, nor can we be sure, any month in the year, that some scout from his low camp may not strike down the tenderest of the children of summer. 

This foe will go on steadily increasing in strength and boldness, till his white camps will be pitched over all the fields, and we shall be compelled to take refuge in our strongholds, with some of summer’s withered spoils stored up in barns, maintaining ourselves and our herds on the seeds and roots and withered grass which we have embarned. Men in anticipation of this time have been busily collecting and curing the green blades all the country over, while they have still some nutriment in them. Cattle and horses have been dragging homeward their winter’s food.