To transfer any impression with vermilion.
Mix the colour with linseed oil in a state sufficiently fluid to flow from the point of a pen, with which let every line of the print be accurately traced; then wet the back of it, and turning the face down wards on clean white dry paper, place other paper on the back, and gently rub or press it, till it may be supposed the red lines are completely transferred to the paper from the print.
Writing, or outlines of prints, may be conveyed exactly by the following me thod. Mix fine vermilion with water, of the same fluidity as ink, and putting it into a vessel containing cotton, use it with a pen in tracing over the subject, making the lines of the same breadth as the original; then wet white paper with gum-water spread by a sponge, and lay the vermilion tracing on it gently, press ing every part till the process is com plete : when the print is withdrawn, the gum will retain the vermilion, and after it is dried they will become inseparable. This mode, except the gum and paper, is used by engravers, who secure the lines by wax on their copperplates.
There are numerous beauties in the skeletons or fibres of leaves : and it is at least a pleasing, if not an useful employ ment, to collect all, or a part of their va rieties, which may be ,thine with decisive accuracy as follows.
To obtain the true shape and fibres of a leaf, rub the back of it gently with any • hard substance, so as to bruise the fibres, then apply a small quantity of linseed oil to their edges ; after which press the leaf on white paper, and, ttion removing it, a perfectly correct representation of every ramification will appear, and the whole may be coloured from the original.
Another way, which may be called printing of a leaf. This is effected by carefully touching the fibres with one of those balls, lightly covered with ink, us ed by printers, and impressing it on wet paper. This is clone to most advantage by a round stick covered with woollen cloth, rolled backwards and forwards over the paper and leuf.
A substitute may be adopted by rub bing and bruisingthe leaf, oiling it as be fore, and scattering powderedblack lead, charcoal, or the powder of burnt cork, on it, and pressing it on paper. Other co lours may be used, prepared with butter or oil, of which blue-bice is the best, as it serves as a ground for colouring the leaf from nature. The back of the leaf must be exclusively preferred, as the fi bres project on that side only.' Stenciling is a process well calculated for multiplying of patterns, for working in muslin, &c.; when a print or drawing is to be copied in this way, it must be placed upon a sheet of white paper, and the outline pricked through both with a pin or needle ; the pierced sheet may then be laid on a second clean one, and a muslin bag of powdered charcoal shaken or rubbed over it, when, upon removing the former, the latter will be found a pefect copy.
The camera obscure makes the most pleasing representation of nature hither to discovered, by which the external ob jects are reflected on any plane within the chamber in the liveliest colours, and every leaf and animal appear in motion but unfortunately in a reversed position. The constructing of a camera obscura is a very simple operation : close all the windows of an apartment, and leave a single circular aperture, suitedfor the re ception of a convex or plane convex lens in the shutter of that which faces the greatest variety of landscape ; then place any smooth white surface before it, at the proper distance, which is to be deter mined upon the same principle as the movement of the glasses of a telescope, and every portion of the view will be ex hibited on it. If the least ray of light makes its way through any other means, the effect will be destroyed ; and it will he heightened, if the atmosphere is clear and the sun shines bright.
The portable camera obscura resembles a wooden box or chest, furnished with a circular or angular projection in the mid dle, opening from it, and to be directed towards the landscape ; beyond this aper ture, and within the box, is placed a small mirror inclined to an angle of 45 degrees, serving to reflect the exterior rays on a convex lens set in a tube, and the light streaming from this will convey the true forms and colours of the land scape to a paper situated at the proper distance to receive them; this beautiful picture is viewed through an oblong aperture, and may he copied with equal facility and advantage ;.Indeecl the most experienced artist may*btain hints from the camera obscura, which might escape his notice in drawing directly from reali ty. The literally darkened chamber fur nishes the means of improvement, though some little contrivance is necessary to use them conveniently, and obviate the unpleasant circumstances attending the drawing the reversed objects ; it may, however, be recollected, that any thing drawn in this position will become right on turning the paper ; or the person de sirous of so doing may place the paper on some low article of furniture, and standing over it, view every part in its proper state; but the portable camera obscura, being expressly intended for making of correct drawings, should be preferred, as it affords a horizontal plane for the band to rest on conveniently.