The grammar of photo-engraving : containing instruction in drawing, chemistry and optics, as applied to photo-engraving, and a practical treatise on the art of half-tone, zinc etching, swelled gelatine, lithotype and chalk plate engraving, as practiced in the United States (1895)
Farquhar, H. D. (Harry D.), Eder, Josef Maria, 1855-1944 · London : Dawbard & Ward · leaf 37
bent at an angle of about 30 deg., with one leg longer than the other. The syphon must first be filled and the shorter leg inserted in the liquid, care being taken to keep its extremity always below the sur- face, and the liquid will flow continuously out of the longer leg as long as there is any… … may be any substance sufficiently spongy or porous to allow free percolation of the liquids. Unsized paper or cotton is generally employed. It is often of great advantage to make a
Photoengraving
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
