They [market gardeners] have created a totally new agriculture. They smile when we boast about the rotation system having permitted us to take from the field one crop every year, or four crops each three years, because their ambition is to have six and nine crape from the very same plot of land during the twelve months. They do not understand our talk about good and bad soils, because they make the soils themselves, and make it in such quantities as to be compelled yearly to seed some of it; otherwise it would raise up the levels of their gardens by half an inch, every year. They aim at cropping, not five or six tons of grass on the acre as we do, but from fifty to one hundred tons of various vegetables on the same space; not 51 pounds worth of hay, but 100 pounds worth of vegetables of the plainest description, cabbages and carrots.[1] [Footnote 1: Kropotkin: _Fields, Factories, and Workshops_, p. 74.] Of intensive industry the same might be said. Where formerly a man could produce only enough for one man's consumption, under conditions of machine production one man's work can supply quantities sufficient for many. With a declining birth-rate and the vastly increased productivity of industry and agriculture, there is a greatly reduced danger of the population growing beyond their possible sustenance by the available food supply. Under certain economic and social conditions there are marked variations in the birth-rate. This may be due to various causes which are, by different writers, variously assigned. The variation of the birth-rate among different classes is again a matter of common observation and statistical certainty. Higher standards of living are found regularly to be correlated with a decrease in the number of children in a family. An important factor in the voluntary restriction of population is the desire to give children that are brought into the world adequate education, environment, and social opportunity. CULTURAL CONTINUITY. To the very young the world seems an unprecedented novelty. It seems scarcely older than their own memories, which are few and short, and their own experience, which is necessarily limited and confined. Through education our experience becomes immeasurably widened; we can vicariously live through the experiences of other people through hearing or reading, and can acquire the racial memory which goes back as far as the records of history, or anthropological research. As we grow older we come to learn that our civilization has a history; that our present has a past. This past extends back through the countless aeons before man walked upright. The past of human life on earth goes back itself over nearly half a million years. With this long past, the present is continuous, being as it were, additional pages in process of being written.