Lea

Collier's New Encyclopedia (1921)

HENRY CHARLES, an Amer- HARTES, an American publisher and historian; born in Philadelphia, d historian; born in Pa., Sept. 19, 1825; entered his father's Sept. 19, 1825; entered publishing house in 1843; became house in 1848the principal in 1865; and in 1865; and retired 1880. Between 1840 and 1860 he wrote many papers 1840 and 1860 he on chemistry and chemistry and conchology. After 1857 he his he devoted bis attention to European mediæval history devoted his chief edieval history works being: "Superstition and Force" uperstition and (1866); "An Historical Sketch of Sacerdotal stoneal Sketchi Celibacy" (1867); "History (1867); "Hisof the Inquisition of the Middle Ages" ( the Middl 1888); "A History of Auricular Confession and of Auricular Indulgences" (1896) "The (1896) Moriscos of Spain" (1901); etc He died in (1901); etc 1909. LEAD (Greek, molybdos; Latin, plum s: Latin, plum bum, whence the chemical symbol Pb) al symbol Pb) This metal was well known to the an own to the an cients. Several lead mines in Great mines in Grea Britain were worked by the Romans Homan with whom the leaden waterpipe were terpipe common. Lead is of bluish is of a white color, and is one of th of th softest of metals. Its ductility an ts ductility an tenacity are low in the scale, but it ma be converted into tolerably thin sheets ably this sheet as well as drawn into wire. It fuses a 325°, and may with difficulty be obtaine in cubic or octahedral crystals; sp. ina. When the petiole is absent the leaf is gr. 11.38. The lead of commerce often nearly pure and can be obtained perfectly so by reduction of the pure nitrate. Metallic lead, exposed to the action of air and pure water, is powerfully corroded, and as a result the water is found to have dissolved the oxide of lead. modify The impurities of most waters this tendency by forming a thin film on the surface of the metal and so preventing any further oxidation. As a sanitary precaution, slate cisterns are greatly to be preferred to leaden ones. Lead enters into the composition of type-metal, pewter, Britannia metal, and plumbers' solder. The best tests for lead are hydric sulphide, which forms a black sulphide, and potassic chromate, which gives chromate. a yellow precipitate of lead