067v - - - - - Files
If they are not trempées à pacquet, that is, in the manner described, with soot, salt, & vinegar, they will not be good. The square large square files used by locksmiths for their rough work are only made of doulx iron, But the soft files must be made of steel. Founders whose work is to repair latten & copper must have their files d coarse otherwise they would fill up with the copper which would make them smooth & soon render them useless. Latten, which is more brittle, welcomes softer files than copper does.
Oxen foot bones for sand
Once having been burned well twice & pulverized, they mold very neatly in sand & need not be reheated, but simply heated with the flame of straw. But if you mold them in a noyau, give it its first layer, simple & very thin, with a pinceau, & leave to dry at ease. Next fortify the following layers with wadding mixed with the said tempered bone sand.
at left middle margin
It is the neatest sand that can be found for copper.
Huiles d’essence
Walnut oil mixed with as much of turpentine & distilled by an alembic renders an essence whiter than common water. But this has no body & does not give a bond for colors that are immediately imbibed, and then leaves the color without stickiness and faded. These, imbibed in this way, would not let you work or soften, no more than in distemper. But you rectify this fault, by giving it a little body with turpentine, not at all so thick as for varnish. And thus you can work with azur d’esmail & will make a perfect lead white. Turpentine varnish made with this oil is dry in one hour.