Weekly national intelligencer., 1850-10-26
AGRICULTURAL CHEMISTRY.

Professor JoHssroN, in the Of lectures delivered bv
him before the New York State Agricultural Society," stated
the following things worth remembering:
l. In this climate the temperature rises to 1909 Fahrenhet
hve feet below the surface and l4Oo half an inch below
facts which, he says, be learned himself with surprise
ne uses nem 70 illustrate the economy OF Mature promo
ting vegetation.
The sunbeam composed Of three distinct and separate
raysone Of beat Of light and called the chemical
ray These three sgences exist in different proportions ~
the sunbeam In the spring. summer and autumn The bue
or chemical ray greater in the spng the light greater ia
the summer The chemical ray s less in autumn and then
the heating ray predomnass The proportions these rays
vary in different Of the year order that the growing
plant may arrive maturity. Il has also been ssceaned
that the proportions of these agents vary in different climates
g. It has been ascened that the flower Of plant absorbs
more heat than the other parts and the dark than the
light and hence inferred that the color of ower
what determines the quantity Of heat requires and the
amount which Nature supplies. VA
e. Drainage is necessary in dry and sandy as in wet
soils soil is merely burnt up by drought and you sup
pose the roots descend only to the depth Of about three
inches s obvious that the heat of the summer dries mn the
land to the roots But by drainage you open up the soil
three feet deep that the rain instead Of flowing of the sur
face descends through the soil thus made pervous to it, the
roots will grow deeper, and while the upper surface is ry
the drought does not reach the roots which are thus enabled
to live longer than they otherwise would
s. Tobacco crop which contains much mineral matter
suppose an acre to yield 500 bs these will contain
about l60 lbs of mineral matter which s carried off by the
CROP and D this way the land will soon be exhausted In
four years. 600 bs Of mineral matter would be- carried of
from an acree Of tobacco land the duty the farmer
to supply the mineral matter thus specially exhausted he
wishes to sustain the soil '3fd
g. There are certain parts Of every portion Of every animal
removed every day. and quantity Of materiaYu in its
place. Hence the animal should have constant supply in
order that this daily waste may be made up An ANIMAL re-
qulres to sustain its body in good condition, supply
what called the sustaining food about one-sxeh part Of
its own weight daily you wish to increase It's size OF en-
able i to work, you must give you fssdfor milk
twice the quantity.
will be found that the soil and the plant contain nearly
the same substances the only one not in the plant being
ahstna The mechanical function of aumina in the soil
s to anchor the plant Its tenaciy its available property
Some plants grow in mere sand but the great majority Of
them require certain degree Of tenacty in the SOIL which
obtained BY mixing silica with clay This alumina does
enter INTO the plant but only gives to the soil the enay
cessary to retain the plant.
The above Of the topics discussed in the collection
OF Lectures on the general relations ch science bea-sto
practical agriculture, deiuered By Prot. Jumes r. W.
Johnston, r r. s. s. de-, ,cith notes, &c. published by
U M. Saxton, ofNew York.-NeO York Epening Post.