Nutritive Values of different Crops. 
or rather balanced, when the root is wcio^hed in water.* Still, in 
practice, a more serious source of uncertainty remains. Roots by 
drying, without proportionate shrinking, may, indeed must, have 
some of their interstices filled with air; and thus, when weighed 
in water, appear lighter than they really are. Still, as this indi- 
cates the loss of water only, which is neutral as to specific weight, 
and negative as to nourishment, it does not perhaps entirely vitiate 
the criterion, particularly if it should be found that the specific 
gravities of the roots themselves correspond pretty uniformly with 
their nutritive powers, as inferred from chemical analysis or actual 
experience. None of the published tables which have fallen 
under my eye notice the specific weights of any agricultual pro- 
ductions; and suspecting them not to have been hitherto taken, 
I thought it worth while last year to take those of the turnip, the 
swede, the mangold wurzel, and the potato ; but having reason to 
apprehend, from an inadvertence, a source of inaccuracy, these 
experiments have this year been repeated, I'oughly, it must be ad- 
mitted, but still with as much accuracy as circumstances allowed. 
As the subject has not, I believe, been hitherto investigated, their 
publication may lead to further and useful inquiry. I beg, how- 
ever, to premise that I only offer them with that view ; and as for 
the speculations which accompany them, they are intended chiefly 
as illustrative of the advantages which may accrue from ascer- 
taining and recording even such dry and abstract facts (if they are 
such) as specific gravities, but by no means as positively drawing 
any conclusions of my own. 
1. 
2. 
Number 
of Roots 
weighed. 
3. 
Specific 
Gia\ity. 
4. 
'Amount of 
Kuti-itive Matter 
iu 1000 pavts. 
Analysis. 
5. 
Equivalents 
uf Nutrilive 
Power. 
Experience. 
6. 
Nitrogen in 
100,000 lbs. 
Turnips . . 
SiveJes . . . 
Jtangold wurzcl . 
Potatoes . . . 
17 
24 
36 
CO 
898-6 
901'65 
1016-35 
1095- 
421 
64 >Herapatb. 
139] 
274 Eynhoff. 
500 
397 Geel. 
200 
200 
370 
Hence it will be seen that the order of the specific gravities 
coincides with that of the three following columns, as far as they 
* The use of tlie sacchavometev with liquids is exactly this : — It gives the 
weight of those very ingredients, minus that of the water in which tliey are 
held in solution ; and, for all practical purposes, the saccharometer is con- 
sidered as giving a true standard of nutritive contents, notwithstanding the 
similar objection, that the liquids to which it is applied (as in barley) con- 
tain precisely the same soluble ingredients as the vegetable.— W. II. H. 
