(a) 0.51 gram per litre.
(b) 24.6 parts per 100,000.
(c) Solution taken, 100 c.c.; copper found, 0.0045 gram.
(c) " 50 c.c.; iron found, 0.165 gram.

8. Convert into ozs. (troy) per ton:--
(a) 7 loths per centner.
(b) 30 grams per quintal.
(c) 15 parts per 100,000.

FOOTNOTES:

[1] Ether or carbon bisulphide.

[2] Such substances are best dried by pressing between folds of dry
filter-paper.




CHAPTER II.

METHODS OF ASSAYING.--DRY GRAVIMETRIC METHODS.


The methods of assaying are best classed under two heads, Gravimetric
and Volumetric, in the former of which the final results are weighed,
whilst in the latter they are measured. A commoner and older division is
expressed in the terms much used in practice--wet assays and dry assays.
Wet assays include all those in which solvents, &c. (liquid at the