MIAULIS, Andreas Vohos, or Bokos, Greek admiral: b. Negropont, about 1768; d. Athens, 24 June 1835. His family name was Vokos or Bokos, his surname Miaulis being derived from the Turkish word for a felucca. He was a wealthy merchant captain living on the Island of Hydra at the outbreak of the Greek war of independence in 1821, and was appointed to the command of the Greek fleet. He assisted at the relief of besieged Missolonghi in 1822-23, and succeeded in blocking the Turks' further advances after their capture of Psara in 1824. He was able to supply troops and stores to Missolonghi in the second siege of 1825, although he could not prevent the fall of the town. He was outnum bered by the Egyptian naval forces, but suc ceeded in hampering their movements. He was superseded in the command of the Greek naval forces by Lord Dundonald in 1827, and there after ably supported his successor, the repre sentative of the powers intervening in behalf of Greece. After the establishment of Greek independence he was a vigorous antagonist of Capodistrias and the Russian party, and again commanded the fleet in the insurrection of 1831. He was one of the deputation commissioned to offer the Greek crown to King Otho, and he remained his staunch supporter. He was named by King Otho rear-admiral, and later, vice-admiral.
MICA (Lat. mico, flash), a mineral group, marked by high basal cleavage, and laminae which may be made very thin by a process of continued separation. The micas are silicates; muscovite, the commonest, is a silicate of potas sium and aluminum, and is often styled potas sium mica; paragonite, or sodium mica, corre sponds closely to muscovite, but has sodium in stead of potassium; biotite, a silicate of mag nesium, potassium and iron, is marked by its darker tints, and is commonly called magnesium iron mica; lepidolite is a lithium mica, with fluorine, potassium and aluminum in its com position, and a rose tint. Mica is widely scat tered in North America and Asia, especially India. Ruby colored mica, no matter what itS provenance, is now called (Indian.° Europe has no commercial supply. Deposits are most frequently found in pegmatite (q.v.) dikes, varying in 'thickness from a few inches to several hundred feet, and correspondingly in length. Many other minerals accompany it, especially quartz and feldspar, and the mica is scattered through the dike, or vein, as the miners call it. Moreover, scarcely more than
10 per cent, and sometimes as little as 2 per cent, is commercially useful. Mica was well known in prehistoric America, traces of its use being widespread. A great shaft near Mount Mitchell, in North Carolina, was discovered in 1869. This not merely solved the nuestion as to the origin of the early supply, but gave the first impulse to the mining of mica in the United States. Mica lands in North Carolina became tremendously valuable. This boom was quickly followed by the development of the in dustry in southern New Hampshire; and this in turn by important discoveries, in the 80's, in Canada and India. In Quebec, Ottawa and Perth and Renfrew counties, Ontario, the sup ply is of excellent quality, and hence is easily mined and cheap. Hindu labor and an excellent grade of mica make the output of Bengal, Bom bay and the Madras presidency even cheaper. To classify the various sources of supply roughly, it may be said that India gives the world one-half, and Canada and the United States each about one-fourth of the entire sup ply. Everywhere the (veins° start near the surface; hence mining is simple. In New Hampshire there has been a break from the primitive methods, but in North Carolina, ap parently the richest field in the United States, the mining is still unorganized, being done al most entirely by farmers, with the simplest of tools, between crops. In this region, mica is largely used as a medium of exchange between farmers and storekeepers.
In 1870 mica waste was first utilized by Frederick Beck, who introduced the use of "mica-flour,° or ground mica, as a coating for cheap wall-papers. Scrap-mica, formerly worth less, rose to $17 a ton, and then gradually fell to $6 or $7. This branch of the business is confined to the United States. Since 1895 there has been a fresh and most important use for mica, namely, as an insulator. For this pur pose the sheets are split very thin and glued to cloth, then wound into rings for armatures. As a result of this variation of the uses of mica, only the colorless sorts, notably muscovite, are largely used for lamp chimneys and stove doors. Mica is also valuable as a lubricant, as an ab sorbent of glycerine in making dynamite, and, in the case of the lithium silicates, such as lepido lite, in the manufacture of lithium salts. See MINERAL PRODUCTION OF THE UNITED STATES.