216 GEOLOGICAL SURVEY 
by first drying a weighed portion of the soil, until it ceases to lose weight; it is then completely 
saturated with water, placed upon a piece of bibulous paper, and when the water ceases to drop 
from it, the whole is weighed. The increase of weight is due, of course, to the water imbibed. 
In this manner the following results were obtained. 
Kinds of earth. Water absorbed by 100 
parts of the earth. 
Silicious)sande: S2e2 26ae2).< cence ae 25 
Gypsumye == = eee eee ee eee Q7 
@alcareousisandeee 2a= eae ae woe eae eee 29 
SandyAclaysecese nese eosap eee ae ae 40 
Strong clayeee se ena eee Se ee ee 50 
SandiiClayeeee on ne eee eee 70 
Hine*calcareoustearth. 22 -.2ece se eee 85 
iumustee See 20 2S ere eee 90) 
Garden. carthitos cole e eee See eee 89 
Mra blevsollomeec, ace See ee aoe eee eee 52 
It appears from these experiments that sands have least imbibing power, and that calcareous 
soils stand higher than clays, while those earths that contain much vegetable matter in the state of 
humus, rank highest. In comparing the power of calcareous earth, with that of calcareous sand, 
we see how soils are affected, in this respect, by the state of subdivision of the ingredients—show- 
ing the necessity of attending to the physical, as well as chemical, properties of soils. 
Tenacity and Pliability of Soils—The terms stiff, and light, applied to soils, indicate different 
degrees of tenacity or pliability; and the resistance presented to the plough by the soil is the mea- 
sure of this property. This resistance is made up of two forees—the tenacity or cohesion of the 
soil, and its adhesion to the plough. The following table exhibits the comparative tenacity alone. 
Kinds of earth. Tenacity. 
Siliciousgsan dese = eee ess See eee 0 
@aleaneousibandsee eae ease ae oo eee ne 0 
Hine: calcareous earth=——----=-5—-2.-—--- 5.0 
FEMS Bee tee ree eel UE ee Se 8- 
Sandyaclay ee poe oose ces eee esac 57.3 
Stitt iclayey sols. 26 ee eee 2 == 000 
Sinon etc layaeee nae aa eee eee 83.3 
Pune iclay Meet Sp. ca. See Be 100.0 
Gardengearth=. -- 54) 22 4 ee wee ee 7.6 
There appears to be no direct relation between the power of a svil to imbibe moisture, and its 
tenacity ; for calcareous earths, which imbibe more water than clays, are far less tenacious ; and 
water makes sandy soils stiffer. 
The power of frost to reduce the tenacity of soils is well known. ‘'This is due to the expansion 
of the water in freezing, which separates the particles of the soil; and hence the advantage of Fall 
ploughing. The tenacity of a soil, which was 68, fell to 45, after the action of frost. 
Disposition to become dry, or power of retaining moisture.—The rapidity with which a soil 
throws off moisture, by evaporation, has an important bearing on its fertility, as well as the ease 
with which it may be worked. The terms cold, and warm, soils, have, in general, reference to this 
property, which is next in importance to the power of imbibing moisture. 
