SIR--I would feel happy should the few remarks I will at present offer
be found worthy of insertion in your columns--it is on the subject of
waterproofing cloth, or other fabrics, cotton, silk, leather, &c.
When the matter first came before the public, being determined if
possible to ascertain the secret, after many unsuccessful experiments I
found all the requisite properties to consist in a concentrated solution
of acetate of alumina, which can be procured at a cheap and a moderate
rate, by mixing equal quantities of sulphate of alum (common alum) and
acetate of lead (sugar of lead), and dissolving them in water: one pound
of each may be purchased for one shilling, which may be dissolved in
one gallon and a half of boiling water, and well mixed; when cold, the
supernatant liquid should be removed from the sediment, which consists of
sulphates of lead, potash, &c. Any article of dress, no matter how slight
the fabric, if well saturated in it, and allowed to dry slowly, will
bear the action of boiling water, and not permit it to pass through: it
is a remarkable fact, and there are many others connected with the same
solution well worthy of investigation. I should be glad if some of your
learned correspondents would favour us with the reason why the boiling
water will not pass through, and the steam of the water will. Thinking it
a subject not totally unworthy of examination, I remain, Sir, your most
obedient servant,
THOMAS IRWIN,
Apothecary and Chemist, 48 Cuffe St.