OCR Text |
Show Gold Film Ib Transparent Cold 1-2,709,000 of nn Inch thick, or 10,58-1 times thinner than the ordinary ordi-nary sheet of printing paper has recently re-cently been produced. Ono grain of tho precious metal of this thickness covers nearly four square feet of area and Is perfectly transparent The process of obtaining tho thinnest thin-nest film Is to cut a sheet of copper to a determined size and place It ln nn electric bath, whoro sufllclont gold Is deposited' on ono surface of the plate, to produco tho flnost gold color discernible. To separate tho film of gold from tho copper, tho gold-plated copper strip la lmmorsed ln a weak solution of nitric acid for several days. Tho coppor Is entirely dissolved, leaving tho film of gold floating on tho surface of tho liquid. Tho film la then collected on a glass plate Popular Popu-lar Sclenco Monthly. |