210 
Tlip Pirsent State of Ar/riailtiire 
body of agricultural experiments which have hitherto been col- 
lected together. From these experiments, and from others made 
in England and Germany, certain important deductions may be 
safely drawn — such as, — 
a. That substances rich in nilro2:en increase the verdure, 
lengthen the straw, and generally promote and prolong the growth 
of plants. 
b. That lime, in its more common forms, generally shortens 
the period of growth, strengthens the stem, and hastens the time 
of ripening, both of corn and root crops. 
c. That certain saline substances, applied alone, and even in 
comparatively minute quantity, produce a remarkable — what may 
almost be called a marvellous effect — upon certain crops on cer- 
tain soils. 
d. But change the crop, or the soil, or the season, or apply them 
in the same circumstances a second or a third time, and frequently 
no sensible effect will follow. 
e. That where one substance applied alone refuses to produce 
a visible effect, a mixture of two or more may give rise to striking 
differences. 
J". That phosphoric acid, lime, and certain forms of organic 
matter are essential constituents of such a mixture as shall every- 
where^ and in all circumstances, produce a marked and bene- 
ficial effect on old cultivated land, to which no other manure is 
applied. 
Such general deductions as these are Important bases for future 
practical researches, and perhaps to have attained a degree of 
certainty in regard to them alone is worth all the expenditure 
the experiments have cost. We have, indeed, other more special 
conclusions which may be regarded tis prohahle ; for instance — 
a. That the so-called soluble saline substances — the salts of 
potash, soda, magnesia, &c. — are giateful to our root crops, in 
which they largely exist. 
h. That those which contain sulphuric acid have a specially 
beneficial action upon leguminous plants. 
c. That the use of common salt adds weight to the grain. 
d. That on mossy land the use of bones tends to fill the ear. 
e. That lime and salt are better than lime alone on some soils, 
in giving strength to the straw. 
f. That mineral manures, applied alone, act like lime, in 
shortening the period of growth. 
Such yrohahlc- deductions are not without an actual money 
value as guides to the practical man; but they are almost beyond 
price to an advancing science, as they point the way to new 
experimental researches, by which the donuiia of ascertained 
truih \^ill be cn'arged. 
