"'The results obtained with the insoluble phosphates has cost usually less than one-half as much as that with the soluble phosphates. Insoluble South Carolina phosphate rock produced a higher total average yield than dissolved South Carolina rock.' "The Rhode Island director comments as follows: "' With the pea, oat, summer squash, crimson clover, Japanese millet, golden millet, white podded Adzuka bean, soy bean, and potato, raw phosphate gave very good results; but with the flat turnip, table beet, and cabbage it was relatively very inefficient.' "The following statement is from the Massachusetts director: "'It is possible to produce profitable crops of most kinds by liberal use of natural phosphates, and in a long series of years there might be a considerable money saving in depending at least in part upon these rather than upon the higher priced dissolved phosphates.' "The director of the Maine State Experiment Station gives us the following: "'For the first year the largest increase of crop was produced by soluble phosphate. For the second and third years without further addition of fertilizers, better results were obtained from the plots where stable manure and insoluble phosphates had been used.' "The stable manure and insoluble phosphates here referred to were not applied together, but on separate plots. In deed, the raw phosphate was not used in connection with manure either in Maryland, Rhode Island, Massachusetts, Maine, Pennsylvania, or Indiana; and in the extensive experiments in progress in Illinois the raw phosphate has been used, as a rule, not with farm manure, but with green manures; and wherever manure has been used in connection with the raw phosphate, as in Ohio, the comparison is made with the same amounts of manure applied without phosphate. "The Pennsylvania Report for 1895, page 210, contains the following statement: "'The yearly average for the twelve years gives us a gain per acre of $2.83 from insoluble ground bone, $2.45 from insoluble South Caroline rock, $1.61 from reverted phosphate, and 48 cents from soluble phosphate, thus giving us considerably better results from the two forms of insoluble phosphate than from the reverted or soluble forms.' "The Indiana director reports as follows: "'It will be seen that during the first and second years the rock phosphate produced little effect, while the acid phosphate very materially increased the yields. During the third and fourth seasons, however, the rock produced very striking results, even forging ahead of the acid. This and very similar investigations in progress lead us to believe that rock phosphate is a cheap and effective source of phosphorus where immediate returns are not required.