of Phosphoric Acid, equal to 38.40 per cent, of Bone Phosphate of
Lime, or nearly 39 per cent.; 1.81 or nearly 2 of this Phosphoric Acid
is soluble in water, and is, therefore, equivalent in its effects of five
times the Bone Phosphate of Lime that it represents. See Patent Of-
fice Report, 1852-8, Agricultural, page 391.

Making the most liberal allowance as above, and estimating bones to
be worth $25 per 2,000 lbs., (ton) we may say that in consideration of
the soluble Phosphoric Acid, the phosphates in this compound are worth,

per ton.............................................................. $25 00

And the Ammonia.......................................... 10 00

Whereas, if we estimate the Phosphates in Peruvian
guano at same rate, the 500 lbs. of Phosphates in

Peruvian Guano would be............................. 12 50

And the 320 lbs. of Ammonia in a ton of Peruvian
Guano would be.............................................35 24

$47 74

In view of the above analysis, I do not hesitate to say that this ma-
nure is cheaper to many farmers at forty dollars per ton than Peruvian
Guano at fifty; and believing as I do, that there is no species of manure
for any crop, and much less for all soils, I still reiterate the opinion ex-
pressed several years since, that these combinations of Peruvian Guano
are more generally certain than the Guano alone, which fails on many
farms to produce any good effect.

I have given its absolute value, or money value—also my opinion of
its price—and it is my intention to apply one ton to my corn field this
year where its use is indicated, and where I am sure it will compare fa-
vorably with any other manure. Respectfully,

David Stewart, M. D.
Baltimore, 79 North Eutaw Street.

We see at first sight that the above does not represent a Super
Phosphate at all. Where is the necessary Sulphuric Acid ? This
is a question which the analysis cannot answer.

We read in one place:

"Salts, Potash and Soda, Sulphuric Acid, &c, 5.55," and at
another:

"Potash and Soda."

Now if Potash and Soda make 2 per cent, by themselves, then,
of course, Salts of Potash and Soda must make at least 5 per
cent. Deduct these 5 per cent, from the whole amount allowed
for Salts, Potash and Soda, Sulphuric Acid and &c, which is
5.55 as above mentioned, and we have half of one per cent, for
Sulphuric Acid and &c, and therefore in a favorable case one-
fourth of one per cent, of "&c." and one-fourth of one per cent,
of "Sulphuric Acid." This amount of Sulphuric Acid is so
small as must be considered an incidental impurity, and not as

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