The panel should be cypress or pear or service-tree or walnut. You must coat it over with mastic and turpentine twice distilled and white or, if you like, lime, and put it in a frame so that it may expand and shrink according to its moisture and dryness. Then give it [a coat] of aqua vitae in which you have dissolved arsenic or [corrosive] sublimate, 2 or 3 times. Then apply boiled linseed oil in such a way as that it may penetrate every part, and before it is cold rub it well with a cloth to dry it. Over this apply liquid varnish and white with a stick, then wash it with urine when it is dry, and dry it again. Then pounce and outline your drawing finely and over it lay a priming of 30 parts of verdigris with one of verdigris with two of yellow. [Footnote: M. RAVAISSON'S reading varies from mine in the following passages: 1._opero allor [?] bo [alloro?]_ = "_ou bien de [laurier]_." 6. _fregalo bene con un panno_. He reads _pane_ for _panno_ and renders it. "_Frotte le bien avec un pain de facon [jusqu'a ce] qu'il_" etc. 7. _colla stecca po laua_. He reads "_polacca_" = "_avec le couteau de bois [?] polonais [?]_."] The preparation of oils (629--634). 629. OIL. Make some oil of mustard seed; and if you wish to make it with greater ease mix the ground seeds with linseed oil and put it all under the press. 630. TO REMOVE THE SMELL OF OIL. Take the rank oil and put ten pints into a jar and make a mark on the jar at the height of the oil; then add to it a pint of vinegar and make it boil till the oil has sunk to the level of the mark and thus you will be certain that the oil is returned to its original quantity and the vinegar will have gone off in vapour, carrying with it the evil smell; and I believe you may do the same with nut oil or any other oil that smells badly. 631. Since walnuts are enveloped in a thin rind, which partakes of the nature of ..., if you do not remove it when you make the oil from them, this skin tinges the oil, and when you work with it this skin separates from the oil and rises to the surface of the painting, and this is what makes it change. 632. TO RESTORE OIL COLOURS THAT HAVE BECOME DRY. If you want to restore oil colours that have become dry keep them soaking in soft soap for a night and, with your finger, mix them up with the soft soap; then pour them into a cup and wash them with water, and in this way you can restore colours that have got dry. But take care that each colour has its own vessel to itself adding the colour by degrees as you restore it and mind that they are thoroughly softened, and when you wish to use them for tempera wash them five and six times with spring water, and leave them to settle; if the soft soap should be thick with any of the colours pass it through a filter. [Footnote: The same remark applies to these sections as to No. 618 and 619.] 633. OIL. Mustard seed pounded with linseed oil. 634.