The art of glass shewing how to make all sorts of glass, crystal and enamel : likewise the making of pearls, precious stones, china and looking-glasses : to which is added, the method of painting on glass and enameling : also how to extract the colours from minerals, metals, herbs and flowers ... : illustrated with proper sculptures / written originally in French, by Mr. H. Blancourt, and now first translated into English ; with an appendix, containing exact instructions for making glass-eyes of all colours.

CHAP. LXXI. Another Fairer and Whiter Colour.

THIS second way of giving Milk White to Glass, is much better than the precedent, and the Working more exquisite. We only make use of the Calx of Tin, without mixing any Lead; and we put sixty Pound of that Calx, to four hundred Pound of pure Crystal Fritt, with two Pounds and an half of Manganese of Piedmont prepared; the whole being well pulverized and mixed, must be put in a Pot heated in the Furnace, there to purifie during eight Days: Then cast the Matter into the Water the bet∣ter to purifie it, then put it to melt again in the same Pot, after having dry'd it. If it be transpa∣rent, you must add to it fifteen Pound of the same Calx of Tin as before, mixing it well with the melt∣ed Metal, to make it the better incorporate; twen∣ty four Hours afterward, it will be finer and whiter than Snow, and ready to work.