Paper Condenser.
The paper used in the manufacture of the commercial form is a special thin, tough linen paper carefully selected, sheet by sheet, to avoid pin-holes or flaws, and kept in an oven until used to ensure absolute dryness.
When this cannot be procured, use thin unsized writing paper of a good quality, well dried, and absolutely clean. As an example of the necessity of cleanliness, a light lead-pencil mark would serve to conduct the current entirely from a charged sheet to wherever it terminated, and if suitably located, utterly destroy the usefulness of the apparatus. Ink, which most generally contains iron, will cause trouble, and although some cheap foreign condensers are built up of old ledger pages, yet their efficiency is very uncertain.
The paper used in commercial condensers is from four to seven thousandths of an inch in thickness.