"In all your operations diligently observe the processes which you read, and vary not a little from them, for sometimes a small mistake or neglect spoils the whole operation, and frustrates your expectations.
"Try not at first experiments of great cost, or great difficulty; for it will be a great discouragement to thee, and thou wilt be very apt to mistake.
"If any one would enter upon the practices of Chymistry, let him apply himself to some expert artist for to be instructed in the manual operation of things; for by this means he will learn more in two months, than he can by his practice and study in seven years, as also avoid much pains and cost, and redeem much time which else of necessity he will lose."
[Fig. VIII. p. 82], represents a common cold still, and [Fig. IX. p. 84], is a sketch of an apparatus for distilling by the aid of boiling water. The bath wherein the vessels are placed in Fig. IX. was called by the alchemists balneum Mariae, from Mary the Jewess, who is mentioned in the older alchemical writings, and is supposed to have invented an apparatus of this character. Nothing definite is known of Mary the Jewess. A writer of the 7th century says she was initiated in the sacred art in the temple of Memphis; a legend prevailed among some of the alchemists that she was the sister of Moses.
[Fig. X. p. 85], represents methods of distilling with an apparatus for cooling the volatile products; the lower vessel is an alembic, with a long neck, the upper part of which passes through a vessel containing cold water.
Fig XIII. See p. [94.]
[Fig. XI. p. 88], shows a pelican, that is a vessel wherein a liquid might be heated for a long time, and the volatile products be constantly returned to the original vessel.
[Fig. XII. p. 89], represents a retort with a receiver.