were 40,000 tons of nitrate of soda in our
docks, which could not find purchasers, although the price did not
exceed [L]12 or [L]13 per ton.'"

"He evidently thinks," said the Doctor, "that available nitrogen is
cheaper now than it will be in years to come."

"Nitrate of soda," said I, "at the prices named, is only 2-1/2 to 2-3/4
cents per lb., and the nitrogen it contains would cost less than 18
cents per lb., instead of 24 cents, as given by Prof. Johnson."

"No. 1 Peruvian Guano, 'guaranteed,' is now sold," said the Doctor, "at
a price per ton, to be determined by its composition, at the following
rates:
_Value per pound._
Nitrogen (ammonia, 17-1/2 c.) 21-3/4 c.
Soluble phosphoric acid 10 c.
Reverted " " 8 c.
Insoluble " " 2 c.
Potash, as sulphate and phosphate 7-1/2 c.

"The first cargo of Peruvian guano, sold under this guarantee,
contained:

_Value per ton_.
Ammonia 6.8 per cent $23.80
Soluble phosphoric acid 3.8 " " 7.60
Reverted " " 11.5 " " 18.40
Insoluble " " 3.0 " " 1.20
Potash 3.7 " " 5.55
------
Estimated retail price per ton of 2,000 lbs. $56.55
Marked on bags for sale $56.00

The second cargo, sold under this guarantee, contained:

_Value per ton_.
Ammonia 11.5 per cent $40.50
Soluble phosphoric acid 5.4 " " 10.80
Reverted " " 10.0 " " 16.00
Insoluble " " 1.7 " " .68
Potash 2.3 " " 3.45
------
$71.43
Selling price marked on bags $70.00

"It is interesting," said I, "to compare these analyses of Peruvian
guano of to-day, with Peruvian guano brought to England twenty-nine or
thirty years ago. I saw at Rothamsted thirty years ago a bag of guano
that contained 22 per cent of ammonia. And farmers could then buy guano
guaranteed by the dealers (not by the agents of the Peruvian
Government), to contai