Essays on Peat, Muck, and Commercial Manures. E-book. Formato PDF Samuel W. Johnson   -  Forgotten Books, 2017  - 

Manures are substances which are incorporated with the soil for the purpose of supplying some deficiency in the latter. How ever numerous and different may be the materials which assist the growth of plants, judging them by their origin, external characters and names, chemistry has in late years demonstrated that they all consist of only about a dozen forms of matter, ~which will be specified below.