Impression wax for vents.
| Beeswax | 4 parts. |
| Tallow | 2 parts. |
| Charcoal, finely powdered | 1 part. |
Melt the beeswax and tallow, and stir in the charcoal.
Paper parchment.
Immerse unsized paper for a few seconds in sulphuric acid, diluted with half its volume of water at about 60°; wash it well in cold water, then immerse it in a weak solution of caustic ammonia, and again wash.
It absorbs water, and becomes soft and pliable like animal parchment, but is water-proof. It is not affected by boiling water, is indestructible by most acids, and is not diminished in strength by wetting. It has about 2/3 the strength of animal parchment when dry; the thinner kinds make capital tracing-paper, which takes ink readily.
Cement for the above.
| Cheese—fresh, without salt, if possible | 3 parts. |
| Quicklime | 1 part. |
Wash the cheese thoroughly three or four times in boiling water, and grind the materials on a stone and muller, adding cold water until it is of the consistency of honey.