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Scan 293
Old Violins And Their Makers, 1883
4 lines. Read by computer on 27 September 2026. Printed page 279. See the scan on archive.org.
1the colour without becoming turbid. This liquid, composed of essential oil and alcohol, would not have communicated sufficient elasticity to the resins, and the varnish would have been too dry. It therefore became necessary to find a means to eliminate the alcohol, in order to obtain the pure essence charged with the colouring matter. This operation was not a difficult one, as alcohol boils at about 171deg. F., while the essentials oils do not begin until they attain a much higher temperature. The mixture was therefore treated with a water bath, in which the water could not rise beyond its boiling point, 212deg. F., a heat inferior to that which is necessary to evaporate the essences, and it was anticipated that the alcohol alone would go. That is precisely what happened, and the essence, disembarrassed of the former, used only as a solvent, remained charged with the colour with which it had been mixed. This liquid was then allowed to rest during eight days, at the end of which time it had undergone no alteration. A coloured varnish was then made and applied to a piece of wood, sized as already described, and abandoned to the action of the sun for a month, and at the termination of this period it had lost nothing of its tint. This experiment was repeated with an alcoholic solution of dragon's blood, and the result was as satisfactory. Phials of this coloured varnish were kept for between two and three years, and on the expiry of that time not the least deposit had formed.
3In order, however, to ensure success in these experiments, it is necessary that the essential oils employed be very pure. A simple means of discovering if they
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