Fifth. We ought not to expect to grow clover where we have taken away the necessary substances for its growth in the corn crop. CHAPTER XXII. ON THE WEEDS OF CLOVERS. That clover crops are often very full of weeds every farmer must be fully aware, but few among them have used sufficient penetration to have discovered the source of most of the weed growth, not only in clovers, but in other crops: how much, then, may they be expected to be astonished if told that they cultivate weeds by sowing their seeds as carefully as they do those of their crops, and that they pay the same price for weed as for crop seeds! In the spring of 1859 we published the results of some analyses of the weed admixtures in several samples of different kinds of clover seeds, which we annex (table 1, p. 149), adding to them some further results obtained during the present spring, 1863, by way of comparison. This presents a formidable array of figures, as it shows how much of more than mere harmless matter is purchased and sown instead of good seed; and the fact of the mischief likely to accrue from putting so many enemies in the place of friends will become all the more plain by a careful study of the next table (No. 2, p. 150). Now, in order to make this part of our argument still more complete, we add another table (No. 3, p. 150), intending to show the number of weed plants absolutely separated from a single square yard of old seeds taken from a field on the great oolite rock. 1. TABLE OF WEEDS IN CLOVER SEEDS.