1. Silica, 1 part; carbonate of soda, 2 parts; fuse together. 2. Carbonate of soda, (dry.) 54 parts; dry carbonate of potassa, 70 parts; silica, 192 parts; soluble in boiling water, yielding a fine transparent, semi-elastic varnish. 3. Carbonate of potassa, (dry,) 10 parts; powdered quartz for sand, free from iron or alumina,) 15 parts; charcoal, 1 part; all fused together. Soluble in 5 or 6 times its weight of boiling water. The filtered solution evaportaed to dryness yields a transparent glass, permanent in the air.