pure from them, or be recognised by its smell when burning. This gave
rise to the sulphur theory, while the presence of mercury was inferred
doubtless from the resemblance of the more commonly molten metals,
silver, tin, and lead, to quicksilver. The properties of each metal
were then put down to the presence of these substances. The list of
seven metals is that of the most ancient times--gold, electrum,
silver, copper, tin, lead, iron; but it is clearly recognised that
electrum is an alloy of gold and silver.

Most of the facts in this book are derived from Pliny through Isidore,
but, that the theory is Arab in origin, one fact alone would convince
us. A consideration of the composition of the metals shows us that tin
is nearest in properties of all metals to the precious ones, but tin
is precisely the metal chosen by Arab alchemists as a starting-point
in the Chrysopoeia.

Beside their scientific interest these passages have supplied many
analogies. When Troilus is piling up his lover's oaths to Cressida,
his final words are:

"As iron to adamant, as earth to centre;"

our chapter on the adamant supplies the origin of this allusion in
part, astronomy gives the other. Diamonds are still, unfortunately,
the precious stones of reconciliation and of love our author bespeaks
them. The editor has not lengthened the chapter by extracts giving the
occult properties of gems, and has contented himself by quoting from
the chapter on glass a new simile and an old story.

Matter and form are principles of all bodily things; and privation of