Democratic Sentinel, Volume 10, Number 51, Rensselaer, Jasper County, 21 January 1887 — The Thinnest Gold Leaf. [ARTICLE]

The Thinnest Gold Leaf.

A recent experimenter says that by electroplating a known weight of gold upon one side of a sheet of copper foil of given dimensions, a coating of gold may be obtained upon the copper, whose thickness is readily ascertainable by a simple calculation; then by using a suitable solvent the copper may be removed, when the leaf of gold will remain intact. After a series of careful experiments he obtained in this way sheets of gold mounted on glass plates, which are not more than the 1-40,000 of a millimetre in thickness, and he had some specimens which he believed were not more than the 1-10,000 of a millimetre. To give an idea of its in thickness, or rather thinness, it may be said that it is about 1-200 part of the length of a wave of light. Taking Sir William Thompson’s estimate of the size of the final molecules, and considering that each layer of molecules corresponds to one page of a book, the thinnest film would then make a pamphlet having more than a hundred pages. Dr. J. Strahan utters a caution against long-continued dosing with mixtures of iron, maintaining that there is danger of intestinal concretions being formed.