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green tinge, and never, so far as I have observed, a goi’dyellow.

Neri directs, for a gold yellow colour, one part of red.tartar, and the fame quantity of manganese, to be mixedwith a hundred parts of fritt or the composition for glass.

Kunkel, in his experimental remarks on Neri, fays thatthis process gave him more trouble than any other in thebook; that the proportions are quite faulty; that the quan-tity of manganese is too much for the tartar,, and the tar-tar too little for the fritt; that one part, or one and a quar-ter of manganese, is sufficient for a hundred of fritt, butthat six parts of tartar are hardly enough, especially unlessthe tartar is of a dark red colour almost blackish ; and thathe found it expedient to add to the tartar about a fourthof its weight of powdered charcoal. He takes notice thatthe composition swells up greatly in melting; that if theglass be much stirred with the iron, as is customary forother kinds of glass, it will rife up so as to run over thepot, though at first no more than half full; and that there-fore it must be left unstirred, and worked as it stands in fu-sion. Speaking afterwards of a yellow enamel tingedwith the same materials, he adds, that the colour must becarefully watched, too long a continuance of fire destroy-ing it.

My ingenious friend Mr. Samuel More, in repeatingand varying this process with a view to render the colourmore perfect, found that the manganese is entirely inessen-tial to the gold colour, and that the tartar is no otherwiseof use, than in virtue of the coaly matter to which it is inpart reduced by the fire, Different kinds of coals, as thatof tartar,, common charcoal, foot, dried blood, &c. on be-ing melted with colourless fritts or glasses, gave always.pale yellow, dark yellow, reddish, brownish, or blackishcolours, according as the inflammable matter was in smaller-

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