57

Hence we may state the proportions thus:Coarse Silex 30

Finer •—

2 6

-5 6 parts

Argil] —

14

Calx —

30

100

The use of the gravel

is to keep the soil open,

and loose: a circumstance absolutely necessary,as I have before observed.

The specific gravity is not given, but shouldnot much exceed, I suppose, 1,600. Mus-chenbroek found that of garden-mould 1,630.The carbonic matter was not known to Mr.

Bergman.

The proportion in a

troy pound, supposing

the quantity of water and coal not to exceed

100 grains, stands thus,

omitting fractions:

Gravel

1698

Fine Sand

1471

-3169

Argill -

a

fc-

1

1

Calx -

1698