Page:Treatise on Soap Making.djvu/44

28 when growing in its vegetable form; but, if broken, the inside is of a deeper and more glossy blue. Soza and Salicor are darker, and almost black within, of a heavier consistence, and very little or no sign of spunginess.

All these ashes contain a strong alkali, but barilla the best and purest, though not in the greatest quantity. Upon this principle, it is fittest for making glass, and bleaching linen. The others are used in making soap. Each of them would whiten linen, but all, except barilla, would burn it.

The method used in making barilla is the same as that followed in Britain in burning kelp.

The plant, as soon as ripe, is plucked up, and laid in heaps, then set on fire; the salt juices run out below into a hole made in the ground, where they collect into a vitrified