in Mineralogy; borate of soda, tinhalk, soude boratee. This salt is usually of a white or gray colour, translucent, feebly alkaline to the taste, soluble in water, and consists, according to Klaproth, of soda 14-5, boracic acid 37-0, and water 47-0. It intumesces before the blow-pipe, and then melts into a transparent globule; when in solution it changes the blue colour of litmus into green. Its chief locality is Thibet, where it is found on the surface of the soil, in the vicinity and at the bottom of certain lakes. It is there collected and sent to Europe in the form of a brownish-gray, impure salt, from which the artificial borax is obtained by the addition of a greater quantity of soda. It is made use of as a flux, in forming imitation gems, and in the process of soldering. It is also of great utility in analysis by the blow-pipe, and in some cases in glass manufactories. See Chemistry and Mineralogy.