Coil Boilers

The water from which the steam is to be generated is contained within a coil of wrought iron pipe of of their i ue, while those made by republics or free States have usually some device emblematic of the people or State authorizing their coinage. The devices on coins are of a varied character. Some consist of simple letters or figures stamped or punched in the rudest manner, while others are of the most beautiful form that can be engraved on metal. Ancient coins comprise the coinage of Europe. Egypt and Asia, to the period when the barbarians invaded Europe, putting a stop to the old arts; and are chiefly those of the Greek cities, the Roman, Republic and Empire, the Persian or Part hi an, and the Byzantine. The Greek coins are the oldest extant, and were first struck in gold and silver. They are of various designs, from the rudely struck did rach am of Ægin a, ab. 800 B.C., to the highly finished coins of Sicily and s. Italy, 400-200 В.С., with rarest devices on both sides and elaborate inscriptions. A silver currency was introduced in Rome and a mint established in the temple of Juno Moneta, 269 B.C.; gold was coined 206 B.C. In England the first gold coin on record was struck 1257; sovereigns were struck 1489, shillings 1503, crowns 1553. In the U. S. the first colonial coinage was in Ma . 1652. Vt.and Conn. coined copper 1785; N. J. and Ma . 1786. In the U. S. decimal coinage was adopted; gold eagles and half-eagles, with silver dollars and divisions of a dollar were i ued from 1794-96, and cents and half-cents from 1793. The mechanical execution of American coins is perfect, but the designs have often been criticised as inferior to those of the other leading nations. To insure sufficient hardne , 1 part of alloy is almost universally put with 9 parts of pure gold or silver, but in England the ratio of copper to gold is 1 to 11. India has the same ratio (1 to 11) also for silver. See ASSAY.