To try if it be _Hard_ enough, they put the end of a Stick into the _Oyl_, which will lick up about three or four drops, which they put upon an Oyster-shell, or some such thing, and set it by to cool, and when it is cold they touch it with their Fore or Middle-Finger and Thumb, and try its consistence by sticking together of their Finger and Thumb; for if it draw stiff like strong _Turpentine_ it is Hard enough, if not, they Boyl it longer, or _Burn_ it again till it be so consolidated. When it is well Boyled they throw in an Ounce of Letharge of Silver to every four Gallons of _Oyl_ to Clarifie it, and Boyl it gently once again, and then take it off the Fire to stand and cool, and when it is cool enough to put their Hand in, they Strain it through a Linnen Cloath, and with their Hands wring all the _Varnish_ out into a Leaded Stone Pot or Pan, and keeping it covered, set it by for their use; The longer it stands by the better, because it is less subject to turn Yellow on the Paper that is Printed with it. This is the _Dutch_ way of making _Varnish_, and the way the English _Inck-makers_ ought to use. _Note_, _First_, That the _Varnish_ may be made without _Burning_ the _Oyl_, _viz._ only with well and long Boyling it; for _Burning_ is but a violent way of Boyling, to consolidate it the sooner. _Secondly_, That an _Apple_ or a _Crust_ of _Bread_, _&c._ stuck upon the end of a Stick instead of an _Oynion_ will also make the Scum of the _Oyl_ rise: For it is only the Air contained in the Pores of the _Apple_, _Crust_ or _Oynion_, &c. pressed or forced out by the violent heat of the _Oyl_, that raises the many Bubbles on the top of the _Oyl_: And the connection of those Bubbles are vulgarly called _Scum_. _Thirdly_, The English _Inck-makers_ that often make _Inck_, and that in great quantities, because one Man may serve all _England_, instead of setting a _Caldron_ on a _Trevet_, build a _Furnace_ under a great _Caldron_, and Trim it about so with Brick, that it Boyls far sooner and more securely than on a _Trevet_; because if the _Oyl_ should chance to Boyl over, yet can it not run into the Fire, being Fenced round about with Brick as aforesaid, and the _Stoking-hole_ lying far under the _Caldron_.