148 AGRICULTURAL REPORT. 
the clays are imperfect conductors; and the clayey earths are weak, im- 
perfect conductors. The presence of the moisture and of oxide of iron, 
found in all the clays, appears to be the base of this phenomenon. 
Influence of the simple earths on the germination of seeds—The devel- 
opment of the germ depends upon the looseness, moisture, and tempera- 
ture of the soil, as well as upon its warmth and consistence. 
1. In moist siliceous and calcareous sand the grains germinate in sum- 
mer in afew days, and develop well, but suffer as hot weather approaches. 
2. In gypsum powder they develop indifferently. 
5. In sandy clay no proper development takes place. 
4, This is also the case in loamy and stiff clay. 
5. In pure clay no change whatever occurs, but the grains develop 
well when transferred to proper soil. 
6. In pure carbonate of lime, carbonate of magnesia, and slaty marl, as 
well asin pure humus, garden-mold, and arable soil, the seed germinate 
well—the young plants in warm weather developing themselves most 
beautifully in the humus, and in the carbonate of magnesia, in conse- 
quence, probably, of the greater power of containing water which these 
earths possess. 
Soil as adapted to climate—In such warm countries as have also a 
small mean quantity of rain, those kinds of soil which have a great 
power of containing water will, if other circumstances are the same, be 
the best; while those soils which have, on the contrary, a small power 
of containing water will be found better suited for countries with a 
greater amount of rain. Those very soils, therefore, may be fertile for 
one country which become no longer so fer another, under a change of 
external circumstances; the usual alternation of dry and wet years 
being on the same principle, more favorable to the one or to the other 
country, according as their predominating soils respectively possess a 
greater or less degree of this power of containing water. 
General remarks on the foregoing.—In the examination of soils, the 
determination of their power of containing water, and of their weight, 
consistency, and color, in connection with their chemical analysis, will, 
in the majority of cases, be sufficient to enable us to conclude, with great 
probability, as to their remaining physical properties. The more an 
earth weighs, the greater also in general is its power of retaining heat; 
the darker its colon and at the same time the smaller its power of re- 
taining water, the mere quickly and strongly wili it be heated by the 
sun’s rays; the greater its power of containing water, the more has it 
in general the power also of absorbing moisture from the atmosphere 
when it is in a dry state, and oxygen when it is in a @amp state, and the 
slower it usually is to become dry, especially when it is endued at the 
same time with a high degree of consistency. Lastly, the greater the 
power of containing water, and at the same time, the consistency of a 
soil, the colder and wetter of course that soil will be, as well as the stiffer 
to work, either in a wet or dry state, and the more judicious therefore 
will it be to break it up before the setting in of the frost, in order that 
its consistency may be improved by the due penetration of the frost 
during the winter; and for the cultivation of many plants, the more 
requisite will it be found for the permanent improvement of such a soil, 
te counteract its too great consistency and power of containing water 
by mixing it with. looser earths, as lime, marl, and sand. 
In this and the preceding report, the French thermometrical centigrade 
scale has been used frequently. To convert this into the Fahrenheit 
scale, we must remember that 5 centigrade degrees are equal to 9° 
Fahrenheit; so each centigrade degree amounts to 1.8° of I‘ahrenheit, 
