for Twenty Years in succession on the same Land. 95 
Potass — as sulphate of potass. , 
Soda — as sulphate of soda. 
Maqnesia — as sulphate of magnesia. 
Lime — as sulphate, phosphate, and superphosphate. 
jPhosphoric acid — as bone-ash, mixed with sulphuric acid in 
quantity sufficient to convert most of the insoluble earthy 
phosphate of lime into sulphate and soluble superphos- 
phate of lime. 
Sulphuric acid — in the phosphatic mixture just mentioned ; 
^ in sulphates of potass, soda, and magnesia ; in sulphate of 
ammonia, &c. 
Chlorine — in muriate of ammonia. 
Silica — as artificial silicate of soda. 
Other constituents have been supplied as under: — 
Nitrogen — as sulphate and muriate of ammonia ; as nitrate 
of soda ; in farmyard manure ; in rape-cake. 
Non-nitro(jenous organic matter, yielding by decomposition 
carbonic acid, and other products — in farmyard manure, in 
rape-cake. 
The artificial manure or mixture for each plot is ground up, 
or otherwise mixed, with a sufficient quantity of soil and turf- 
ashes to make it up to a convenient measure for equal distribution 
over the land. The mixtures so prepared are, with proper pre- 
cautions, sown broadcast by hand ; as it has been found that the 
application of an exact amount of manure, to a limited area of 
land, can be best accomplished in that way. 
The Field Eesults. 
The results obtained with barley will be arranged and 
discussed under separate heads, adopting much the same division 
of the subject as in the report on the experiments with wheat, 
but following a somewhat different order of illustration. 
Accordingly, they will be considered in Sections as under : — 
I. — Quantity and quality of the produce obtained, by different 
descriptions of manure, in each of the twenty seasons ; with 
summary statements of the characters of each season. 
II. — Average annual produce obtained over many years in 
succession, by each description of manure employed. 
III. — Amount of ammonia in manure (or its equivalent of 
nitrogen in other forms), required to yield a given increase of 
grain (and its proportion of straw), according to the quantity 
applied per acre, to the available supply of mineral constituents 
within the soil, and to the characters of the season, 
IV. — Effects of the unexhausted residue from previous manuring 
