Prof. Norton on the Analysis of the Oat. 323 
The very large per-centage of silica is one of the most striking 
features in this table. It amounts in every case to more than 70, 
and in Hopeton oats, No. 3, to more than 80 per cent, averaging 
considerably higher than in any other part of the plant. It is no 
doubt present in such quantity that the husk may be a proper 
covering to the grain. While the husk is yet green, the chaff, as 
I have stated, protects both it and the grain; but this is only un- 
til the husk arrives at maturity; it is then, by itself, admirably 
fitted to protect the grain, and the chaff is no longer necessary. 
In the salts soluble in water, sulphuric acid still predominates ; 
phosphoric acid is usually there also, but in minute quantities, 
and the phosphates in the acid solution seldom amount to more 
than 1 or 2 per cent. In two of these analyses there is no soda, 
neither is it found in the ash from the grain of the same oats. 
The two alkalies seem to fulfill the same purpose in the economy 
of the plant, and it appears to take one or both indifferently, as 
they are more or less abundant in the soil. 
_ The above table has shown that the ash of the husk varies in 
its composition, but I have prepared another in a condensed form, 
which exhibits the fact more distinctly. 
Composition of Ash from four samples of Oat Husk. 
Taste XXX. 
Hopeto 8. | Potato [Dun oats,| 
No. 1, Light/No. 2, Poor oats, Grav-| Good 
lsandy loam | moss. __|_elly soil. loam. . 
Salts soluble in water, chiefly sulphates 22-92 33-84 93-14 19-96 
and chlorid. 
Phosphates of lime, ma nesia, and iron 1-84 462 | 110 249 
Linen. tad thagiiipecrn «uke ain noble 154 | 518 | 328 
no, eta 68:55 | 60-00 | 70:57 | 74-25_ 
100-00 10000 | 9999" | 99-98 
any part of the plant to which it belongs. Its demands, as mo 
imperative, seem to have been supplied first. sous 
No part of the plant has so small a portion of salts soluble in 
water as the husk. From the instance of the Dun oat above, 
they may even be below 20 per cent. in a perfectly healthy sam- 
ple, for this was inferior to none in general appearance and size. 
. Composition of the Ash from the Grain.—With this last 
part of the plant I shall follow the same plan as I have hitherto 
pursued, first giving extended analyses, and then directing atten- 
tion to the differences caused by variety of soil, manure, &c. 
