Scientific American, New Series 8, 22.2.1862
To prepare gold ink, take honey and gold leaf equal parts; grind together upon a painter's porphyry slab with a muller, until the gold is reduced to the fines possible state of division, and the mass becomes perfectly homogeneous, when it must be agitated with 20 or 30 times its weight of hot water, and then allowed to settle and the water poured off; this process must be repeated with fresh water 2 or 3 times, when the gold must dried and then mixed up with a little weak gum water for use. The brilliancy of writing performed with this ink is considerable, and may be increased by burnisching. Gold ink may also be made by mixing precipitated gold powder with a little gum water. Silver ink is prepared in the same manner as the gold. By dissolving gold in aqua regia and then adding ether, a solution is obtained which, when applied to polished iron, will coat it with a thin pellicle of gold.