A History of Inventions, Discoveries, and Origins (Vol. 1&2). Johann Beckmann

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СКАЧАТЬ Hellot’s experiments were made known in Germany, it was affirmed that Professor H. F. Teichmeyer, at Jena, had prepared the same ink six years before, and shown it to his scholars, in the course of his lectures, under the name of sympathetic ink270. It appears, however, that it was invented, even before Teichmeyer, in the beginning of the last century by a German lady. This is confirmed by Pot, who says that the authoress of a book printed in 1705, which he quotes under the unintelligible title of D. J. W. in clave, had given a proper receipt for preparing the above-mentioned red salt, and the ink produced by it271. If it be true that Theophrastus Paracelsus, by means of this invention, could represent a garden in winter, it must be undoubtedly older272.

[In consequence of the progress of modern chemistry and the discovery of a vast number of new chemical compounds, sympathetic inks may be made in an almost endless number and variety. The principal may be classed in the following manner:—1, such as when dried upon paper being invisible, on moistening with another liquid become again evident: of this kind there are a vast number; among which we may mention a solution of a soluble salt of lead, or bismuth, for writing, and a solution of sulphuretted hydrogen for washing over; the writing then appears black; or green vitriol for writing and prussiate of potash for washing over, when the writing becomes blue273; 2, such as are rendered evident by being sifted over with some powder, as the milk with soot described above; 3, those which become visible by heat, such as characters in dilute sulphuric acid, lemon-juice, solutions of the nitrate and chloride of cobalt, and of chloride of copper; the two former become black or brown, the latter are rendered green, the colouring disappearing subsequently when allowed to cool in a moist place. Amusing pictures are sometimes made with these sympathetic inks, particularly those composed of cobalt; for if a landscape be drawn to represent winter, the vegetation being covered with a solution of cobalt, on holding the paper to the fire, all those portions covered with the solution appear of a bright green, and thus completely change the character of the scene.]

      FOOTNOTES

260 De Arte Amandi, lib. iii. v. 629.

261 Ausonii Epist. xxiii. v. 21. The poet afterwards teaches other methods of secret writing, and Gellius, lib. xvii. cap. 9, mentions the like.

262 Colum. De Re Rust. x. 354. and xi. 3, 60.

263 Plin. lib. xxvi. cap. 8. p. 400.

264 The sixth observation of the second century is as follows: Magnetic waters which act at a distance. An astonishing effect, indeed, is produced by the contest of the following waters, which are thus made. Let quick-lime be quenched in common water, and while quenching, let some orpiment be added to it (this however ought to be done by placing warm ashes under it for a whole day), and let the liquor be filtered, and preserved in a glass bottle well corked. Then boil litharge of gold well pounded, for half an hour with vinegar in a brass vessel, and filter the whole through paper, and preserve it also in a bottle closely corked. If you write any thing with this last water with a clean pen, the writing will be invisible when dry; but if it be washed over with the first water it will become instantly black. In this, however, there is nothing astonishing; but this is wonderful, that though sheets of paper without number, and even a board be placed between the invisible writing and the second liquid, it will have the same effect, and turn the writing black, penetrating the wood and paper without leaving any traces of its action, which is certainly surprising; but a fetid smell, occasioned by the mutual action of the liquids, deters many from making the experiment. I am, however, of opinion, that I could improve this secret by a more refined chemical preparation, so that it should perform its effect through a wall. This secret I received, in exchange for others, from J. Brosson, a learned and ingenious apothecary of Montpelier.

265 Tachenii Hippocraticæ Medicinæ Clavis, p. 236. 1669.

266 Collectanea Chymica Leydensia, edidit Morley. Lugd. Bat. 1684, 4to, p. 97.

267 For an account of various kinds of secret writing see Halle, Magie oder Zauberkräfte der Natur. Berlin, 1783, 8vo, v. i. p. 138.

268 Hist. et Mém. de l’Acad. des Sciences à Paris, 1737, pp. 101 and 228.

269 Historia Cadmiæ fossilis, sive Cobalti. Berl. 1744.

270 This account, together with Teichmeyer’s receipt for preparing it, may be found in Commercium Litterarium Norimbergense, 1737, p. 91.

271 “Copiosius minera bismuthi tam ab aqua forti quam ab aqua regia dissolvitur, restante pulvere albo corroso; solutio in aqua forti roseum colorem sistit, quæ si sali in aqua soluto, secundum præscriptum D. J. W. in clave, affundatur, abstrahatur, ex residuo extrahitur sal roseum, quod pulverisari et cum spiritu vini extrahi potest: adeoque hæc autrix jam anno 1705 publice totum processum et fundamentum sic dicti atramenti sympathetici, quod a calore viridescit, evulgavit.”—Pot, Observ. Chym. collectio prima. Berolini, 1739, p. 163.

272 So thinks Gesner in Selecta Physico-œconomica, or Sammlung von allerhand zur Naturgeschichte gehörigen Begebenheiten. Stutgard, vii. p. 22.

273

[Inks formed of solutions of the following salts,	and washed with solutions of	become
Muriate of antimony,	tincture of galls,	yellow.
Green vitriol,	tincture of galls,	black.
Nitrate of cobalt,	oxalic acid,	blue.
Subacetate of lead,	hydriodic acid,	yellow.
Arseniate of potash,	nitrate of copper,	green.
Nitrate of copper,	prussiate of potash,	brown.
Solution of gold,	muriate of tin,	purple.
Perchloride of mercury,	hydrochlorate of tin,	black.]

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