, of pearl-ash, soda-ash, or
a mixture of 1 part medicinal carbonate of magnesia, and 4 parts
magnesian limestone. The mixtures, of course, all lost weight
considerably by the evolution of water and carbonic acid.]

[Note 4: Made with unburnt bones.]

[Note 5: In this first season, neither the weight nor the measure
of the offal corn was recorded separately; and in former papers, the
bushels and pecks of total corn (including offal) have erroneously
been given as dressed corn. To bring the records more in conformity
with those relating to the other years, 5 per cent, by weight, has
been deducted from the total corn previously stated as dressed corn,
and is recorded as offal corn; this being about the probable
proportion, judging from the character of the season, the bulk of
the crop, and the weight per bushel of the dressed corn. Although not
strictly correct, the statements of dressed corn, as amended in this
somewhat arbitrary way, will approximate more nearly to the truth, and
be more comparable with those relating to other seasons, than those
hitherto recorded.]

These were the results of the harvest of 1844. The first year of these
since celebrated experiments.

If Mr. Lawes expected that the crops would be in proportion to the
minerals supplied in the manure, he must have been greatly disappointed.
The plot without manure of any kind, gave 15 bushels of wheat per acre;
700 lbs. of superphosphate of lime, made from burnt bones, produced only
38 lbs. or about half a bushel more grain per acre, and 4 lbs. _less_
straw than was obtained without manure. 640 lbs. of superphosphate, and
65 lbs. of commercial sulphate of ammonia (equal to about 14 lbs. of
ammonia), gave a little over 19-1/2 bushels of dressed wheat per acre.
As compared with the plot having 700 lbs. of superphosphate per acre,
this 14 lbs. of available ammonia per acre, or, say 11-1/2 lbs.
nitrogen, gave an increase of 324 lbs. of grain, and 252 lbs. of straw,
or a total increase of 576 lbs. of grain and straw.

On plot No. 19, 81 lbs. of sulphate ammonia, with minerals, produces
24-1/4 bushels per acre. This yield is clearly due to the ammonia.

The rape-cake contains about 5 per cent of nitrogen, and is also rich in
minerals and _carbonaceous matter_. It gives an increase, but not as
large in proportion to the nitrogen furnished, as the sulphate of
ammonia. And the same remarks apply to the 14 tons of farm-yard ma