Analyses of Ashes of Plants. 
649 
the character of the season, locality, aspect, climate, treatment, 
&c., and we cannot hope to add anythin<^ to what is already 
known on this highly important subject. We may mention that 
the mean produce, over more than 40 specimens, has been found 
to be 28 bushels of grain, of a mean weight of 61 lbs. to the 
bushel. 
The amount of straw in comparison with that of grain, is also 
in the same way very closely connected with the varying condi- 
tions in which the crop has existed ; but upon this individual ques- 
tion our results would seem to throw some light. We are not 
ignorant that many careful observers have endeavoured to dis- 
cover the general relationship in quantity which the straw of wheat 
bears to the grain ; but we think that these determinations have 
seldom hitherto been conducted over so large a number of speci- 
mens, in such varying conditions as regards soil and cultivation, 
or with the same amount of analytical accuracy as the present. 
Granted that weighings on the large scale are in many respects, 
when carefully conducted, capable of a nearer approach to abso- 
lute truth, than the results which a chemist obtains by the help 
of his balance — that is to say, when his errors, although of exces- 
sively trifling amount in themselves, are by multiplication into 
tons instead of grains magnified to a very great extent ; but this 
reasoning only applies to those determinations on the large scale 
where every circumstance is taken into account. Now the straw 
of wheat is not (as will presently be seen) all solid matter, but 
contains more than a tenth part of its weight of water. It is true 
that the quantity of water in the straw is not subject to much 
deviation, being comprised within very narrow limits, which we 
need not at present mention ; but the water which is natural to 
it — ^so to speak — it never loses, except by the application of 
artificial heat much higher than that produced by natural agen- 
cies, such as the rays of the sun or the warm atmosphere. On 
the other hand, although straw has always a certain amount of 
this natural water, it may contain a large additional quantity of 
accidental moisture. In other words, it may be really wet. 
Now in ascertaining the proportion of straw to grain on the large 
scale, this circumstance cannot fail of proving a fertile source of 
error; for supposing that a quantity of wheat be removed for 
weighing from the field, who is to say (without careful experi- 
ment) how much accidental water it contains, and how far such 
calculations will be interfered with in consequence ? 
Even in the rick, where a large quantity of straw is closely 
packed together, although it is known to dry to a considerable 
extent, we can hardly suppose that it ever attains the condition of 
dryness which is natm-al to it. But it may be argued, that we 
