THALLIUM n.
aluminium group found in some minerals, as certain pyrites, and also in the lead-chamber deposit in the manufacture of sulphuric acid. It is isolated as a heavy, soft, bluish white metal, easily oxidized in moist air, but preserved by keeping under water. Symbol Tl. Atomic weight 203.7.
TILL n.
A deposit of clay, sand, and gravel, without lamination, formed in a glacier valley by means of the waters derived from the melting glaciers; -- sometimes applied to alluvium of an upper river terrace, when not laminated, and appearing as if formed in the same manner.
TUBERCLE n.
A small mass or aggregation of morbid matter; especially, the deposit which accompanies scrofula or phthisis. This is composed of a hard, grayish, or yellowish, translucent or opaque matter, which gradually softens, and excites suppuration in its vicinity. It is most frequently found in the lungs, causing consumption.…