Columella says with regard to the selection of land that there are two things chiefly to be considered, the wholesomeness of the air and the fruitfulness of the place, "of which if either the one or the other should be wanting, and notwithstanding anyone should have a mind to dwell there, he must have lost his senses and ought to be conveyed to his kinfolk to take care of him." In selecting a farm do not fail to inquire whether there has been any recent illness, and if so the nature of it, either among the persons living there or the domestic animals kept. Aside from healthfulness, climate is a fundamental and controlling factor, both in productiveness and economic farm management. Temperature and rainfall affect the number of days that work can be performed upon the land and hence affect materially the economy of labor. It is this fact that prevents the systematic organization of labor so common in manufacturing and transportation. The climate also affects the cost of producing live stock by modifying the food and shelter required. The climate of a region is best studied from the reports of the United States Weather Bureau rather than from the statements published by interested parties. So far as the production of crops is concerned the distribution of rainfall is more important than the annual amount, as may be shown by comparing the rainfall in such places as Columbus, Ohio, and Lincoln, Nebraska. The average temperature during the growing season is, of course, of more importance from the standpoint of crop production than the average annual temperature. Maximum and minimum temperatures or the range of temperature must be considered as well as the average temperature. One of the most practical questions to determine is the average date of the last killing frost in the spring and the date of the first killing frost in the autumn; in other words, the length of the growing season. Both altitude and topography enter into this problem. In a given locality killing frosts will occur on a still night in the valley before they do on the elevations, because the air as it cools becomes heavier and flows down into the lowest places just as water would do. On the other hand, as the altitude increases the growing season shortens. Whenever I am asked a question involving the production of farm crops by a Pennsylvania farmer before answering, I ask three questions: (1) Where are you located? (2) Do chestnut trees grow naturally upon your land? (3) What is your altitude?