323. The Writer, unacquainted with what had then been done in this Matter, coud not help remarking the striking Properties of the Cochuc in its present Form, to answer every Intention of the best Varnish, if its Price was lower;—viz. compact, pliant, unadhesive, and unalterable by Weather;—if it coud be dissolved, and afterwards made to recover its present unadhesive Form: an Art in which the East and West-Indians are still our Masters.
He has, however, after expensive Trials and Combinations, been able to reduce it into a limpid Liquor.
As it may prove a useful Ingredient for Air-tight Varnish; the Secret he now discovers to the World: and it is merely this.
324. “Take any Quantity of the Cochuc, as two Ounces Averdupois: cut it into small Bits, with a Pair of Scissars.
Put a strong Iron-Ladle (such as Plumbers or Glaziers melt their Lead in) over a common Pit-Coal or other Fire.
The Fire must be gentle, glowing, and without Smoke.
When the Ladle is hot, much below a red Heat; put a single Bit into the Ladle.
If black Smoke issues, it will presently flame, and disappear: or it will evaporate without Flame: the Ladle is then too hot.
When the Ladle is less hot, put in a second Bit, which will produce a white Smoke.
This white Smoke will continue during the Operation, and evaporate the Cochuc: therefore no Time is to be lost: but little Bits are to be put in, a few at a Time, till the whole are melted. It shoud be continually and gently stirred with an Iron or Brass Spoon.