ETCHING ON GLASS—GLASS-CUTTING.

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said- to be of a blue green colour. From the novelty ofthis colour, it nearly superseded, for some length of time,the use of the original and most proper species. That of ablue colour was certainly made by an apothecary of themame of Luce, at Lisle; the blue colour he gave it is con-jectured to have come from using spirit of sal ammoniacwith the oil of amber instead of a purer alkali.

ETCHING on GLASS and GLASS-CUTTING.

Without entering into the history of the lapidary’s art,we only propose to speak of those things which ancientand modern authors have said upon the art of engravingon glass, observing, that it was an art evidently known toboth the Greeks and Romans. Although it appears ex-tremely probable, that, from their confessed ignorance ofmany of those properties which modern chymistry has dis-covered to belong to matter, they were ignorant of the artof etching on glass.

From antique specimens still preserved, a doubt cannotfor a moment be suffered to exist on our mind but that theart of engraving upon glass was familiar to the Greekartists, who formed upon glass both linear figures, and alsoin relievo, by the same means as are now employed for nearlysimilar purposes, if we can place any credit in an able andlearned lapidary, Natter , 1 who has established that theancients employed the same kind of instruments for thispurpose, or nearly such as are now in use; abating,perhaps, the use of diamonds, and the dust of that preciousmaterial: for which it is conceived they employed emerypowder, and the dust of glass.

From what is related by Pliny , it certainly appears thatthey used the lapidary’s wheel, an instrument moving in anhorizontal direction over the work table. Natter’s assertionrenders what Pliny asserts intelligible: Aliud jlutu Jiguratur,aliud tamo teritur, aliud argenti modo calatur . 1

However, in the latter part of this sentence, we mustbelieve the mode employed by silversmiths in the operationof certain engravings, is only alluded unto, for their tools,of necessity, must be essentially different, with the excep-

1 Traitfc de la Methode antique de graver en Pierres fines, compart avec lemethode moderne; par Laur. Natter. Londres , 1754, fol.

* Lib. xxxvi. 26. p. 758.

VOL. II.

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