unvitrified

For some distance from the furnace, this flue may be made of brick or unvitrified sewer pipe, but stove-pipe may be used for the greater part of the run.

Manual of Gardening (Second Edition) 1906

I consider even the pearlstone as an unvitrified obsidian: for among the minerals in the

Travels to the Equinoctial Regions of America 1851

I consider even the pearlstone as an unvitrified obsidian: for among the minerals in the King's cabinet at Berlin there are volcanic glasses from Lipari, in which we see striated crystalites, of a pearl-grey colour, and of an earthy appearance, forming gradual approaches to a granular lithoid lava, like the pearlstone of Cinapecuaro, in Mexico.

Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 1 Alexander von Humboldt 1814

These experiments prove, that a stone which is fusible only at thirty-eight degrees of Wedgwood's pyrometer, yields a glass that softens at fourteen degrees; and that this glass, melted again and unvitrified (glastenized), is fusible again only at thirty-five degrees of the same pyrometer.

Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 1 Alexander von Humboldt 1814

The term glastenized glass is employed by Dr. Thompson and others to indicate glass which by slow cooling is wholly unvitrified, and has assumed the appearance of a fossil substance, or real glass-stone.]

Travels to the Equinoctial Regions of America 1851

Wedgwood’s pyrometer, yields a glass that softens at fourteen degrees; and that this glass, melted again and unvitrified (glastenized), is fusible again only at thirty-five degrees of the same pyrometer.

Travels to the Equinoctial Regions of America 1851

The term glastenized glass is employed by Dr. Thompson and others to indicate glass which by slow cooling is wholly unvitrified, and has assumed the appearance of a fossil substance, or real glass-stone.)

Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 1 Alexander von Humboldt 1814