AGRICULTURAL METEOROLOGY. — 115 
into consideration, and which shows again what an important bearing 
temperature has upon agriculture, is the following: In England, farm- 
ers believe that if the night temperature falls to 40° ¥., there is no 
growth for twenty-four hours, and that the mean temperature of the 
succeeding day may be expected to be about 46°. In this country a 
similar law must prevail, probably with different degrees of heat. Then, 
by observing the monthly charts, and taking note of those localities 
where temperatures are less than 40°, one would ascertain the places 
where, during certain.months, there is little growth—a very important 
question in discussing the crops of the United States. 
’ The most useful temperature in agriculture is that required to ripen 
cereals. It has been proved by observations made by persons compet- 
ing for prizes offered by the Marquis of Tweeddale, president of the 
Scottish Meteorological Society, that the ordinary range of temperature 
in Scotland, necessary to ripen cereals, must average 56° F. If it fell 
below that, there was a deficiency in the crop; if it rose above it, the 
crop was so much the better, provided there were rain and other neces- 
sary conditions. After ascertaining in the United States the most favor- 
able degree of temperature to ripen cereals, with the monthly charts 
one could point to those locations where there is some hazard in raising 
these crops—the places, namely, where the necessary temperature is 
scarcely to be expected, or where it occurs so seldom that the risk is too 
great. It is generally admitted that the temperature falls one degree for 
every 300 feet of elevation, so that, supposing at thesealevel there is a tem- 
perature of 589°, at an elevation of 600 feet the temperature would be 
56°, or a temperature sufficient to ripen cereals. In the same manner a 
thousand agricultural problems should be submitted to-strict scientific 
and practical tests as to the influence of climate on our American crops. 
_The meteorological division should have charge of the discussion of 
all the observations and periodical phenomena sent to the Department 
by observers and farmers, in order to publish and distribute the follow- 
ing indications: 
a. Precise instructions upon the manner of observing their instrn- 
ments, and the number and nature of meteorological influences whieh 
exert any action upon vegetation. ; 
b. Charts furnishing by curves the progress of the principal crops, 
connected, with the lines of equal temperature, moisture, rains, frosts, 
and other pernicious or favorable influences. 
e. Annual charts, and for the largest possible number of past years, 
giving the geographical distribution of these same crops compared with 
the same meteorological influences. 
d. Instructions and catalogues of the names of trees and plants for 
the determination of the epochs of foliation, flowering, fructitication, 
and defoliation. 
e. Charts giving the monthly geographical distribution of equal lines 
of foliation, flowering, fructification, and defoliation. 
Jj. The conclusions arising from the discussion of all these observa- 
tions, with their application to agriculture, furnishing in final result the 
knowledge of the exact degrees of heat, moisture, &c., that each physi- 
ological tunction of the different plants requires for vegetating normally, 
and for the greatest production. 
g. The primitive catalogue of Quetelet, for the observation of the. 
periodical phenomena of flowering, comprises two hundred and eighty- 
eight different plants, which were reduced by Fritsch to one hundred 
and eighteen species, the most ordinary of which are found in’ alinost 
all gardens. When the Department of Agriculture determines to pur- 
