 | John Mason Good - 1813 - عدد الصفحات: 714
...in excess, is apt .to render the jzlass milky. Fora perfectly transparent glass, the pearl ashes are found much superior to lead; perhaps better than any...looking-glasses. The materials for making glass must lirst be reduced tu powder, which is done in mortars or by horse-mills. Alter sitting out the coarse... | |
 | Edward T W. Polehampton - 1815 - عدد الصفحات: 688
...in excess, is apt to render the glass milky. For a perfectly transparent glass, the pearl-ashes are found much superior to lead ; perhaps better than...reduced to powder, which is done in mortars or by horse-mills. After sifting out the coarse parts, the proper proportions of silex and flux are mixed... | |
 | Edward T W. Polehampton - 1815 - عدد الصفحات: 712
...in excess, is apt to render the glass milky. For a perfectly transparent glass, the pearl-ashes are found much superior to lead ; perhaps better than...reduced to powder, which is done in mortars or by horse-mills. After sifting out the coarse parts, the proper proportions of silex and flux are mixed... | |
 | Edward Polehampton - 1815 - عدد الصفحات: 710
...in excess, is apt to render the glass milky. For a perfectly transparent gla*s, the pearl-ashes are found much superior to lead ; perhaps better than any other flux, except it be borax, which is too expen. live to be used, except for experiments, or for the best looking. glasses. The materials for... | |
 | John Mason Good - 1819 - عدد الصفحات: 800
...in excess, is apt to render the glass milky. For a perfectly transparent glass, the pearl-ashes are found much superior to lead ; perhaps better than...flux, except it be borax, which is too expensive to he used, except for experiments, or for the best looking-glasses. The materials for making glass must... | |
 | 1825 - عدد الصفحات: 590
...render the glass milky. For a perfectly transparent glass, the pearl-ashes are found much supe-x rior to lead ; perhaps better than any other flux, except...reduced to powder, which is done in mortars or by horse-mills. After sifting out the coarse parts, the proper proportions of silex and flux are mixed... | |
 | Daniel H. Whitney - 1835 - عدد الصفحات: 614
...oxide, when that is used, may be litharge. The materials must first be reduced to powders in mortars or horse mills. After sifting out the coarse parts, the...proportions of silex and flux are mixed together, and kept in the calcining furnace at a moderate heat for five or six hours, frequently stirring it, and... | |
 | Colin MacKenzie - 1853 - عدد الصفحات: 498
...in excess, is apt to render the glass milky. For a perfectly transparent glass, the pearl-ashes are found much superior to lead; perhaps better than any...too expensive to be used, except for experiments, or fur the best looking-glasses. The materials for making glass must first be reduced to |K>wder, which... | |
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For a perfectly transparent glass, the pearl-ashes are found much superior to lead ; perhaps better than any other flux, except it be borax, which is too expensive to be used, except for experiments, or for the best lookingglasses. The materials for making... 