We might continue to cite hundreds of similar cases but propose to pass over into Maryland, and after showing its application there has produced equally beneficial results, travel northward, calling here and there a witness as we proceed. Among others, we may call to the stand in Maryland, will be the editor of the American Farmer, whose testimony we consider almost invaluable, having devoted much attention to the subject, and to whom, and his able correspondents, we desire to award full credit, in this general manner, to save repetition, for much of the information we shall give the readers of several of the succeeding pages. The testimony of witnesses of such high standing, cannot be too highly estimated by those who are anxious to learn how to renovate their worn out farms, or make the rich ones richer. EXPERIMENTS IN MARYLAND. _Effects of guano upon the crop to which it is applied._--Edward Stabler, in the American Farmer, thus speaks of an experiment he made in 1845, soon after the introduction of guano to any extent into this country. "In a field of some 10 acres, one acre was selected near the middle, and extending through the field, so as to embrace any difference of soil, should there be any. On this acre 200 lbs. of Peruvian guano, at a cost of about $5 was sown with the wheat. Adjoining the guano on one side, was manure from the barn yard, at the rate of 25 cart loads to the acre; and on the opposite side (separated by an open drain the whole distance;) ground bones were applied on the balance of the field, at a cost of $6 to the acre; the field equally limed two years preceding. There was no material difference in the time or manner of seeding; except that the manure was lightly cross-ploughed in, and the guano and bones harrowed in with the wheat. "The yield on the guanoed acre was 35 bushels; the adjoining acre with bone, as near as could be estimated by dozens, and compared with the guano, was about 27 bushels; and the manured, about 24 bushels. The season was unusually dry; and the manured portion suffered more from this cause than either of the others; the land being considerably more elevated, and a south exposure." In our opinion Mr. S. is in error in regard to the manured land suffering most from drouth. In our experience we have always found the best effects from Guano, in wet seasons, or upon irrigated land. He says also, "This is one of the most active of all manures; and although he thinks the effect evanescent, it might aid materially in renovating worn out lands." Since that time a great many other Maryland farmers have, undoubtedly come to the same conclusion, for notwithstanding the price, which he thinks too high to justify its extensive use, has not been materially reduced, there is more guano sold in Baltimore than any, or perhaps all the ports in the United States; and the benefits derived from its use upon the worn out lands of Maryland, have been of the most satisfactory character.