10 
EXPERIMENTS WITH TOBACCO. 
water of irrigation to produce the proper moisture, while 
the greater number of hours of sunlight in connection 
with the foregoing, gives peculiar and advantageous con¬ 
ditions of growth. 
THE SOIL. 
The soil here is formed from the disintegrated rocks 
of the adjacent foothills and mountains. The College 
garden has a soil quite similar to a majority of this 
region, and was that upon which the varieties of tobacco 
were grown. Its analysis shows the following constituents 
present, and the per cent, in which each was found: 
Moisture_ 2.78 
Insoluble silica_ 72.71 
Hydrated silica_ 7.07 
Soluble silica_ .04 
Iron, Fe 2 0 3 _ 3.37 
Alumina, Al 2 0 3 _ 4.20 
Phosphoric acid, P 2 0 5 _ .21 
Calcium, CaO_ .70 
Magnesia, MgO_ .85 
Potash, Iv 2 O_ .41 
Soda, Na 2 O_ .71 
Sulphuric acid, S0 3 _ .08 
Chlorine, Cl_ .12 
Carbonic acid, C0 2 _ 2.70 
Volatile and organic matter_ 4.53 
100.66 
of which .02 is nitrogen. 
Coarse gravel_ 34.72 
Fine material_65.28 
FERTILIZERS. 
We have already noticed the fact that fertilizers 
affect the tobacco plant. Heavy manuring increases the 
quantity per acre, but the tobacco is generally of an 
