Detail of a sketch by Edward Haskell in his journal of the 1862 voyage of the merchant ship Tarquin, from Margaret S. Creighton, Dogwatch & Liberty Days: Seafaring Life in the Nineteenth Century (Salem, MA: The Peabody Museum of Salem, 1982), 3.
Here was an old straw hat, the sort of thing people described as "half worn" in the eighteenth and nineteenth centuries, perfect for experimenting with a waterproofing recipe that I first encountered in Mackenzie's Ten Thousand Recipes (1867; pg. 347). This particular recipe appears verbatim in a number of nineteenth-century recipe books, and I've been able to trace it back at least as far as 1814 (pg. 41):
"A Black Varnish for Old Straw or Chip Hats.
Take the best black sealing-wax, half an ounce; rectified spirit of wine, 2 oz.; powder the sealing-wax, and put it with the spirit of wine in a four ounce phial; digest them in a sand heat, or near a fire, till the wax is dissolved; lay it on warm with a fine soft hair-brush, before a fire, or in the sun. It gives a good stiffness to old straw hats, and a beautiful gloss equal to new, and resists wet."
This seems like a straightforward recipe until you begin to take it apart.
Let's start with "spirit of wine." That's pretty simple. Spirits are beverages that have been distilled, and spirit(s) of wine was the result of repeatedly distilling wine. Today, we call the same substance aqua vitae or, in its more pharmaceutical form, ethyl alcohol. Chemically, alcohol acts as a drying agent in this recipe, speeding and stabilizing the drying process. For this experiment, the closest I could get to true spirits of wine at an affordable price was store-bought ethyl alcohol, which has some other chemical additives.
And "the best black sealing-wax"? Well, that gets trickier, given that sealing wax is not as universal a descriptor as ethyl alcohol. Luckily, Mackenzie comes through for us again, on page 357, with a recipe for black sealing wax. I suspect this was also an older recipe, but I've been unable to find it in an earlier source.
"Venice turpentine, 4 1/2 oz.; shellac 9 oz.; colophony 1/2 oz.; lampblack mixed to a paste with oil of turpentine, q.s. [quantum satis/sufficit: a sufficient amount]"
What's all this mysterious stuff, then, and where can we find it today?
Venice turpentine is a solvent made, like all turpentines, by distilling tree resin, in this case that of the western larch. It's still used today by some painters and, more commonly, in the care of horses' hooves. My supply came from Hawthorne Products, who make actual resin-derived (versus synthetic) Venice turpentine.
Shellac is easy. The female lac bug, native to southern and southeastern Asia, excretes this substance as it forms protective tubes on the branches of trees. Once processed, shellac has a variety of uses, especially as a varnish and wood finish. Of course, Mackenzie doesn't specify whether he means dried, pure shellac or the liquified, alcohol-based product sold in most hardware stores. I decided to go with shellac flakes, a wide variety of which are offered on eBay for use in various crafts, because I suspect that's what Mackenzie meant, given that he included turpentine as a solvent.
And colophony? According to the OED, it's "The dark or amber-coloured resin obtained by distilling turpentine with water." Technically, resin/turpentine is what comes out of trees. Venice turpentine and other "spirits of turpentine" are the fluids that evaporate in the distillation process, leaving colophony/rosin. Rosin is used for a variety of purposes today, including in the treatment of string-instrument bows, and there are many varieties available on eBay. It's hard to say if the one I acquired was actually distilled, but I went for it.
Venice turpentine, shellac, colophony, and candles for making lampblack.
Lampblack, used as the pigment in this recipe for black sealing wax, is a fine soot, unburned material left over from some fires (as, in an eponymous example, the soot that forms inside an oil-burning lamp globe). It's quite easy to make, as this primitive skills page testifies. In essence, you capture the smoke and soot emitted from a burning flame on a smooth surface such as a metal or ceramic plate, and then carefully scrape off the black residue. Mackenzie himself described a method (pg. 328) for gathering lampblack from a tin funnel suspended over a lamp, and as we might expect by now his instructions are identical to a set that appeared in numerous recipe books as early as 1804.
Lampblack from a beeswax candle accreting on a spoon.
The more industrial setup I came up with to harvest lots of lampblack from the bottom of a pot over a candle.
With all the ingredients prepared, I was ready to mix up my sealing wax, dissolve it in ethyl alcohol as Mackenzie instructed, and paint up my hat. Sounds simple, right?
Well, about that...