Imperial Privileged National Gazette

and add oyster shells that have been carefully cleaned of their brown outer layer; shake the vessel frequently for 24 hours, and let it stand until the sediment settles. Then filter the separated liquid through unsized paper Paper without "size" (a glue-like glaze) is more absorbent, acting like a filter or blotting paper. into a glass bottle, add 4 loth term: Loth; an old Germanic unit of weight, roughly 14.6 grams or half an ounce of the finest gall nuts term: Gall nuts; growths on oak trees caused by wasps, highly valued in the 18th century for their high tannin content, essential for making permanent black ink, well crushed; place it in a warm spot and shake it diligently for 24 hours. Filter this mixture again through blotting paper, and afterward add a quarter-measure of very pure water. Following this, it must stand again for 24 hours, and if a sediment appears—as is usually the case—it must be filtered once more. Use this liquid hereafter as instructed above.

Instead of wine vinegar, one can also use any other liquid impregnated with a vegetable acid; and instead of gall nuts, one may use oak bark or any other astringent agent from the plant kingdom that turns black or dark when mixed with an iron solution; likewise, instead of oyster shells, any other pure lime-earth calcium carbonate may be used.

However, if one does not desire the copies to be very black, and if the writing ink is of good quality, then moistening with plain water is sufficient.

Depending on whether the described liquid is strong or weak, and depending on whether one wants the copy to be bold or light, long-lasting or merely legible, more or less pure water is added.

The ink which I use for letters that are intended to be copied, I prepare in the following manner:
Take four quarters of spring water,
1 1/2 lbs. Aleppo gall nuts,
1/2 lb. green vitriol term: Green vitriol; iron(II) sulfate, which reacts with the tannins in gall nuts to create black pigment,
1/2 lb. gum arabic term: Gum arabic; a natural gum used to control the ink's viscosity and keep the pigment in suspension,
4 loth of the best alum term: Alum; a chemical salt used here as a mordant to help the ink "fix" to the paper.

Crush all of these very well and pour them into the water; let it stand for 6 to 8 weeks, shake it diligently, and afterward pour the

entire mass through a linen cloth, and bottle it for use; the bottles must be very well corked.

Description of the Rolling Press for Copying.

Fig. 1. represents the rolling press invented by me from the end view. A B C. is one of the uprights of an iron or wooden frame that holds the two rollers together. D D. are two rollers made of wood or metal; *) (turned with the greatest accuracy so that they are perfectly cylindrical) which run on ends of very strong iron axles fixed within them. E E. is a double-ended lever, by means of which the roller to which it is attached is turned. F F. represents the board of the press, upon which the writings to be copied are placed. N N. is a piece of cloth (or another flexible, elastic material) which is placed next to the roller and on top of the document. G. is a very thick and heavy cross-board of wood or metal, which holds the frame together at the base. H H. represents the corner of an ordinary table, to which the press can be secured by means of iron screw-clamps J J. **)

K. is an incision, one of which is found in each end-piece of the frame, and which are filled with elastic steel, or other metal springs, or any other elastic body; these serve to press the two rollers firmly against each other.

L. is a cushion (support) made of metal, which rests on the spring and serves to carry the end of the axle of the bottom roller.

Fig. 2. represents the press from the side. AB. AB. are the two uprights of the frame. DD. are the two rollers. E. is the double-ended lever. G. is the strong, thick board or metal plate which forms the base of the frame. HH. is the table on which the press stands; J. is one of the

*) They can also be made very well from hard wood, with a metal casing that is about 1/8 or 1/4 inch thick.

**) The submitter of this prefers those which are merely placed upon the table and not screwed down at all, such as he has seen in London. They were somewhat larger than those described here and were placed in the middle of the table.