: OF SOUTH CAROLINA. — 217 
“ ‘ 
_. The comparative relative power of the following soils, was ascertained by placing on a small 
“metallic plate, having a narrow rim, a quantity of the soil saturated with moisture. This was sus- 
“pended to the armof a balance, and its weight noted. It was kept at a temperature of 66° Fahr. 
for four hours: the loss of weight, at the end of that time, indicated the water that escaped by 
evaporation. The following are the results. 
Kinds of carth. 100 parts of the water in, 
lost in 4 hours, at 66° Fahr. 
Silicious: sand. 2257264. bt. | See aes 88.4 
Galdanegus sand Bees oom nace = eo a Soe 75.9 
Guy PSUM R= = ie oe es a eas ae ee 717 
SANA Clive eee eee ne eek Ce 210) 
Siaitshiclnysos2 4! _ - =. a a a 2 45.7 
PeOLaye ee ae oe ee eee ce 34.9 
utowGlayene tee eee oo teen eee OI 
Culchreous Bois ae eset Vases 5 Oey eet tel! 28.0 
Ramus Jef ses ee a Ph AE ee 20.5 
drandenu cote vse A ees Se ee 124.3 
The sands, as might be expected, are least retentive, whilst the calcareous soil stands next to a 
garden soil, or loam, in its capacity for retaining moisture; and this explains one of the effects of 
calcareous manures on Jight or sandy soils. 
Shrinking of soils.—The cracking of soils, during the process of drying, is a common occur- 
rence. Schubler has measured this contraction or shrinking of soils by measuring prisms, in a 
moist state, and again, after drying in the shade. 
100 parts, cube, 
Kinds of earth. contracted to. 
Carbonate of lime, in powder- ----------- 95.0 
mandy Clays! oo. 28 ts Seer oe iota 94.0 
ESS CST) ey EN pen peed 91.1 
Stil clayoss 12S... -2 = SSeS nee 88.6 
Pure dlaysst i226 4 Loose aes, 5 aes 81.7 
EUUS et deni oe err Sano e 84.6 
(Cebu inept Nee en ae eee 85.1 
Hygrometric property of soils. —The property of absorbing moisture from the atmosphere 
is independent of the retentive power of soils, and is intimately connected with their porosity, and 
with certain salts which they may contain. Schubler’s experiments show the correctness of 
Davy’s opinion, that the hygrometric property of a soil was indicative of its fertility. This prop- 
erty was determined by exposing known weights of the dry soils in an atmosphere saturated with 
moisture, and at a temperature of 60° to 65° Fahr. 
77.16 grs. of sovl, spread 
over a surface of \41.48 
Kind of earth. sq. inches, absorbed in 
12 howrs. 
Siliatons| sandis4s—. =\-..- o> =... Bee 0 
CnloanGongEssn dso ne om ee 154 
ry SUE ee ee 0.077 
55 
