likewise many methods of effacing writing—restoring decayed paper—and of various modes of secret writing.—The fifth part treats of Inks for writing, made in different countries, of various materials, and colors,—as from gums, woods, the juice of plants, &c., and also of different kinds of varnishes.—The sixth part treats of the various operations of extracting vitriol, and of its chemical uses.
"This work abounds with a great variety of philosophical, chemical and historical knowledge, and will give great entertainment to those who wish for information on this subject.
"Many curious particulars concerning Ink will be found in a "Weckerus de Secretis." (Printed at Basle, in 1612, octavo.)—This gentleman also gives receipts for making Inks of the color of Gold and Silver, composed as well with those materials as without them,—also, directions for making a variety of Inks for secret writing, and for defacing of [effacing] Inks. There are many marvelous particulars in this last work, which will not easily gain credit with the judicious part of mankind."
We have chosen to give Mr. Astle's paragraphs on this subject, entire, "pure and simple," (with no corrections or alterations, except as to a few particulars in
