I shall reproduce illustrations of some of these processes and pieces of apparatus, and quote a few of the directions, given in a book, published in 1664, called _The Art of Distillation_, by John French, Dr.in Physick.
The method recommended by French for hermetically sealing the neck of a glass vessel is shown in Fig.VI.p.80.The neck of the vessel is surrounded by a tray containing burning coals; when the glass melts it is cut off by shears, and then closed by tongs, which are made hot before use.
Fig.VII.p.81, represents a method for covering an open vessel, air-tight, with a receptacle into which a substance may be sublimed from the lower vessel.

The lettering explains the method of using the apparatus.
French gives very practical directions and much sound advice for conducting distillations of various kinds.

The following are specimens of his directions and advice:-- "When you put water into a seething Balneum wherein there are glasses let it be hot, or else thou wilt endanger the breaking of the glasses.
"When thou takest any earthen, or glass vessel from the fire, expose it not to the cold aire too suddenly for fear it should break.
"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.