ls per acre; and 3-1/2 hundred weight of
muriate of potash an increase, on one plot, of eighteen bushels, and on
the other nineteen bushels per acre."

In the same year, 1871, another set of experiments was made on a better
and more loamy soil, which had been in grass for several years. In 1869
it was sown for hay, and in 1870 was broken up and sown to oats, and the
next spring planted with potatoes. The following are some of the
results:

Bushels per acre.

{6-1/4 cwt. superphosphate }
1. {2-1/2 " muriate of potash } 321
{2-1/2 " sulphate of ammonia }

2. {6-1/4 cwt. superphosphate } 296
{2-1/2 " sulphate of ammonia }

3. No manure 252

4. {6-1/4 cwt. superphosphate } 311
{2-1/2 " muriate of potash }

5. 2-1/2 cwt. sulphate of ammonia 238

6. 15 tons farm-yard manure 365

"It is curious," said the Doctor, "that the plot with sulphate of
ammonia alone should produce less than the no-manure plot."

"The sulphate of ammonia," said I, "may have injured the seed, or it may
have produced too luxuriant a growth of vine."

Another series of experiments was made on another portion of the same
field in 1871. The "no-manure" plot produced 337 bushels per acre.
Manures of various kinds were used, but the largest yield, 351 bushels
per acre, was from superphosphate and sulphate of ammonia; fourteen tons
barn-yard manure produce 340 bushels per acre; and Mr. Hunter remarks:
"It is evident that, when the produce of the unmanured soil reaches nine
tons [336 bushels] per acre, there is but little scope for manure of any
kind."

"I do not see," said the Doctor, "that you have answered my question,
but I suppose that, with potatoes at fifty cents a bushel, and wheat at
$1.50 per bushel, artificial manures can be more profitably used on
potatoes than on wheat, and the same is probably true of oats, barley,
corn, etc."

I have long been of the opinion that artificial manures can be applied
to potatoes with more profit than to any other ordinary farm-crop, for
the simple reason that, in this country, potatoes, on the average,
command relatively high prices.

For instance, if average land, without manure, will produce fifteen
bushels of wheat per acre and 100 bushels of potatoes, and a given
quantity of manure costing, say $25, will double the crop, we have, in
the one case, _an i