Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 3, 1802).djvu/34

16&#93; i6] ink: latter suspended, and prevent the formation of crystals, it will be re- quisite to add about the sixth part of gum-arabic, in proportion to the verdigrease. For preparing jed and yelloiv ink, see the articles Red and Yellow. Printing, or Printers' Ink, differs greatly from every other species. It is an oily matter of the consistence of an ointment, the composition of which is, at present, very imperfeftly known, excepting to the few who are em- ployed in its manufa<:>ure. The following recipe, however, has been found to make printing ink of a tolerable good quality : I/et two quarts of linseed-oil be boiled in a vessel capable of holding a triple quantity, over a strong hre, till it emit a thick smoke. It is then to be kindled with a piece of paper, and suffered to burn for the space of a minute, when the flames must be extinguished, by closing the vessel. As soon as the oil be- comes cool, twQ pounds of black resin, and one poiuid of hard soap, cut into thin slices, are to be added ; the mixture again placed over the lire j and, when the ingredients are perfeftiy dissolved, a pound of lamp black, previously sifted, must be incorporated with the mixture ; af- ter which the whole is to be finely- ground on a marble stone. This method of making print- ers' ink is acknowledged to be preferable to the dilfcrent recipes hitherto published. It is, however, much inferior in beauty ot colour to the ink generally used, and is apt to adhere to the types, so as to make an indistinct impression. Good printers' ink, which is easily ■worked, without daubing or tear- ing the paper, while it imparts a fine colour, is a desideratum that tNN* ^vill amply repay the attention nni time bestowed upon its prepara- tion. — See Printing. SympatketicInk, aliquor em- ployed for writing on paper, so that it may retain its natural whiteness after the letters are formed, till it i3 held near the fire, rubbed withano'-* ther liquor, or some other expedient is used to render the charaders legible. Sympathetic inks are prepared from various substances, such as bismuth, lead, &c. Thus, a solu- tion of common sugar of lead in water, if employed with a clean pen, will remain concealed till it is wetted v,'ith a solution of the liver of sulphur, or is exposed to the vapours of such liquid ; in whicll case it will assume a deeper or ligliter brown shade, in proportion to the strength of the sulphureous gas. By the same process, words written with a solution of bismuth in spirit of nitre, will appear of a deep black colour. Another sympathetic ink mayb^ easily prepared, by diluting oil of vitriol with a sufficient quantity of water, to prevent the paper from being corroded. Letters drawn with this fluid are invisible vi'hert dry, but, on being held near the fire, they assume a perfedtly black colour. The juices of lemons, or onions; a solution of sal ammo- niac, &c. will answer a similar pur- pose, though their application is more difficult, and they afterward* require a greater degree of heat. On the subject of removing of discharging spots, occasioned by* difi'erent inks on linen, silk, or woollen cloth, we shall treat un- der the article Spots. INN, a place appointed for thcr reception and entertainment of travellers.