ck, the
so-called _craie-grise_ (phosphatic chalk), containing from 25 to 35 per
cent of phosphate of lime. The higher quality of Belgian phosphate is
pretty well exhausted, and it is the second class that forms the bulk of
the ordinary Belgian phosphate at present exported. The commercial
article contains about 35 to 40 per cent of phosphate, and about 45 per
cent of carbonate of lime. The fact of its poor quality, together with
the large percentage of carbonate of lime it contains, renders its
adoption alone in the manufacture of superphosphate unsuitable. Attempts
have been made to get rid of a portion of this carbonate of lime and to
raise the percentage of phosphate. For this purpose the phosphate has
been calcined, but this was soon found to be a great mistake. Other
means have been adopted, with the result that the percentage has been
increased to 50 per cent. It is consequently used in small quantities
as a drier, for which it is peculiarly suited on account of its
carbonaceous nature, along with the higher-class phosphates. In the year
1886 about 145,000 tons of this phosphate were raised, of which about
45,000 tons were imported into the United Kingdom.

_Somme Phosphate._

Still more recently a discovery of phosphate deposits has been made in
the Somme and Pas de Calais departments in the north of France,
adjoining, and similar in character to, the Belgian deposits. The only
difference between Belgian and French phosphates is, that the latter is
of a higher quality, and contains from 50 to 80 per cent of phosphate of
lime. A very large demand for these phosphates sprang up, and in 1888,
although they had only been worked for some two years, no less than
150,000 tons had been raised, of which about one-half contained from 70
to upwards of 75 per cent. There are four grades in the market,
containing 55 to 60, 60 to 65, 70 to 75, and 75 to 80 per cent of
phosphate of lime. The highest quality furnishes the chief material for
the manufacture of high-grade superphosphates.

_Florida Phosphate._[224]

During the last few years large quantities of phosphates have been
imported from Florida. These are of different qualities, the land rocks
now imported containing from 70 to 80 per cent of phosphate of lime, and
the river phosphate about 60 per cent. The latter class are similar in
composition to the best South Carolina river-phosphates, which they much
resemble.

_Lahn Phosphate._

Phosphate deposits we