2m 
Causes of Fertility or Barrenness of Soils. 
humus undergoes. It has been thought possible that the nitrogen 
of the atmosphere may, under certain circumstances, unite with 
the nascent hydrogen, set free from combination with carbon and 
oxygen. The following analyses of fertile and barren peats are 
taken from tlie article on Soils, in ' Blackie's Encyclopaedia,' and 
are by Mulder and Sprengel : — 
Organic Matter and Com-1 
bined Water / 
Potash 
Soda 
Ammonia 
Lime 
Magnesia 
Peroxide of Iron 
Protoxide of Iron 
Protoxide of Manganese . . 
Alumina 
Phosphoric Acid 
Sulphuric Acid 
Carbonic Acid 
Chlorine 
Soluble Silica 
Insoluble Silica (Clay) 
Loss 
Mulder. 
No. 1. 
12-000 
1-026 
1-972 
•OfiO 
4-092 
- 130 
9-039 
-350 
-288 
1-304 
-46(5 
-896 
6-085 
1- 240 
2- 340 
57-646 
1-006 
100-000 
No. 2. 
12-502 
1- 4301 
2- 069) 
-078 
5- 096 
- 140 
10-3051 
-563/ 
-354 
2-576 
-324 
1-104 
6- 940 
1- 382 
2- 496( 
51 •706' 
•935 
100-000 
SritENGEL. 
No. 3. 
10-90 
•01 
1-00 
-20 
6-30 
9-30 
-13 
•17 
Trace 
71-80 
-19 
No. 4. 
16-70 
-06 
-13 
■03 
-64 
-78 
•11 
•02 
•01 
81-50 
•02 
100-00 ,100-00 
No. 6. 
37-00 
Trace 
Trace 
-32 
-31 
•52 
-45 
Trace 
Trace 
Trace 
61-57 
100-17 
Nos.'l and 2. — Fertile soils of a tract of land in North Holland, gained by- 
embankment from the sea. 
No. 3. — Rich vegetable mould, near Wager, in Germany, flooded by the river. 
No. 4. — Poor sandy mould, near Brunswick. 
No. 5. — Very infertile, peaty soil, near Aurich, in East Friesland. 
No. 6. — Boggy, sterile lands, near Giffhom, in Germany. 
We hardly require reference to tlie foot-notes. A glance at 
the relative proportions of those mineral matters which have been 
spoken of as necessary to vegetation would at once point out the 
fertile from the barren soils. 1 he analysis appeared worthy of 
insertion, as bearing out what was stated above, that the presence 
of vegetable matter alone cannot ensure fertility. The three last 
soils would all be capable of great improvement by the addition 
of large doses of lime, calcareous gravel, or marl ; and in cases 
where such soils rest upon or lie adjacent to a calcareous sub- 
stratum, such mixtures will be practical, and prove in the end very 
remunerative. The presence of a small percentage of vegetable 
matter seems requisite to ensure a fertile soil, and for general 
cultivation is perhaps better than a larger proportion, since cereal 
crops generally do not flourish in the latter case, probably owing 
