Thick disc of unannealed glass, one of ten, made by William. Nicol, c.1830. For use with polarised light to show strain colours. Thick disc of unannealed glass 1825-1835
Slab of unannealed glass, one of ten, made by William. Nicol, c.1830. For use with polarised light to show strain colours. Slab of unannealed glass 1825-1835
Slab of unannealed glass, one of ten, made by William. Nicol, c.1830. For use with polarised light to show strain colours. Slab of unannealed glass 1825-1835
Slab of unannealed glass, one of ten, made by William. Nicol, c.1830. For use with polarised light to show strain colours. Slab of unannealed glass 1825-1835
Slab of unannealed glass, one of ten, made by William. Nicol, c.1830. For use with polarised light to show strain colours. Slab of unannealed glass 1825-1835
Slab of unannealed glass, one of ten, made by William. Nicol, c.1830. For use with polarised light to show strain colours. Slab of unannealed glass 1825-1835
Unannealed glass oval in wood mount (engraved FTC and marked "purchased 1888 from Rev. P. Sleeman") Unannealed glass oval in wood mount (engraved FTC and marked "purchased 1888 from Rev. P. Sleeman")
Slab of unannealed glass, one of ten, made by William. Nicol, c.1830. For use with polarised light to show strain colours. Slab of unannealed glass 1825-1835
Slab of unannealed glass, one of ten, made by William. Nicol, c.1830. For use with polarised light to show strain colours. Slab of unannealed glass 1825-1835