of tomatoes removed. If the crop per acre be the same as above stated, there would be removed from every acre 7.932 pounds of phosphoric acid; or, putting it in whole figures, it would be 8 pounds per acre. That is, 8 pounds of available phos- phoric acid is shipped away in 200 crates of tomatoes, and must be placed on the acre of ground again or the land be that much poorer. The amount of potash in every pound of tomato is .0020786. Comparing this as we did in previous cases, we learn that for every thousand pounds of tomato a little over two pounds of potash is removed. Placing the yield at two hundred crates of 60 pounds, 24.96 pounds of potash are taken out of the soil and sold. We may put this in whole numbers and say 25 pounds are removed with 200 crates of tomatoes. Then, stating it briefly, we remove 18 pounds of nitrogen, 8 pounds of phos- phoric acid and 25 pounds of potash from the field with every 200 crates of tomatoes. COMPARED WITH OTHER CROPS. A crop of tomatoes removes twice as much potash and over 50 per cent. more nitrogen than either a crop of Irish potatoes or sweet potatoes, and nearly twice as much phosphoric acid as Irish potatoes, and more than four times as much as sweet potatoes. EFFECT OF VARYING THE FERTILIZING ELEMENTS. Numerous tests have been made to see what effect a varia- tion in the amount of different elements of fertilizer would have upon the qualities of the fruit. The difference is much less than was thought it would be; indeed, different samples from the same plots show nearly as much variation as samples from different plots. In general, it seems that an abundance of potash has a tendency to produce fruit with slightly less sugar and more acid; and phosphoric acid a tendency to sweeten, while nitrogen pro- duces luxuriant growth.* AMOUNT OF FERTILIZER IN VINES. The vines of an acre contain about 28 pounds of nitrogen, 4 pounds of phosphoric acid and 34 pounds of potash. This is the amount, if it is all saved to the soil, but if the vines are *cf. Md. B. II, p. 63.