INDICTION 146 INDIGO- WHITE cators are also used to determine, by change of color, the precise point at which a liquid ceases to be either acid or alkaline. The chief reagents used as in- dicators are yellow potassic chromate, potassic ferrocyanide, indigo, carmine, litmus, turmeric, Porrier's orange, tro- poeolin, phenolphthalein, eosin, rosalic acid, etc. An instrument for measuring the horse power of a steam engine. Optics. — A finger working in the field of a microscope to point out a special ob- ject within the field of view. Telegraphy. — The dial and mechanism of a dial telegraph. The face has the letters and figures arranged in two con- centric circles. The motion of the hand is continuous in one direction advancing one letter at each closing of the circuit. The movement is effected by clockwork driving a scapewheel, the teeth of which are alternately engaged and released upon opening and closing the circuit, by means of a pawl operated intermediately from the armature of the electro-mag- nets. INDICTION, a declaration or imposi- tion of a tax, an impost, or a prohibition of grave character. The "Cycle of In- diction" is a period of 15 years, not founded on any astronomical occur- rence, but fixed first by Constantine the Great as a fiscal arrangement. It be- gan on Jan. 1, A. D. 313. The Popes adopted it in the year 1582, when the cal- endar was reformed, that year being the 10th of the indiction. The year of the indiction corresponding to any year of our era is thus found : Add 3 to the date, divide the sum by 15, and the remainder is the year of the indiction, the remain- der indicating the 15th of the cycle. 1884 -f 3 Thus = 125, with a remainder 15 of 12. Twelve, therefore, is the indic- tion of that year. There are three other indictions besides Constantine's : the Cesarean or Imperial, the Roman or Pontifical, and that of the Parliaments of France. INDICTMENT, in law, the act of in- dicting or charging a person with a crime or misdemeanor; the state of be- ing indicted; a formal charge against a person or persons for a crime or misde- meanor. Also a written accusation of one or more persons of a crime or mis- demeanor, preferred to and presented on oath by a grand jury. INDIES, the name given by Columbus to his first discoveries in America, which he thought at the time were a part of India. These lands were afterward termed the West Indies, ""hich name the islands still bear. INDIES, EAST, a collective name vaguely applied to Hindustan, Farther India and the Indian Archipelago. See Hindustan; India. INDIES, WEST. See Indies. INDIGESTION, dyspepsia, difficulty of digestion, with slowness and long re- tention of the food in the ."^tomach, great distress after eating, uneasiness at the pit of the stomach, fetid eructations, and unaltered ingesta in the stools. Diges- tion is much retarded, deficiency and abnormality of the gastric juice being a common occurrence. INDIGO, a vegetable dyestuff, yielding a beautiful and very durable blue dye. Many tropical and sub-tropical plants contain a substance, probably a gluco- side, which, on being extracted and al- lowed to ferment, produces impure in- digo. The plants from which it is chiefly obtained are the various species of Indigofera, I satis tinctoria, Poly- goman tinctorium, etc. Commercial in- digo is by no means pure indigo-blue; it contains indigo-gluten, indigo-brown, and indigo-red, together with insoluble im- purities. Indigo prepared in Java by Sayer's process contains from 66 to 71 per cent, of indigo-blue, and only 2^/^ per cent, of ash, while ordinary commercial indigo seldom contains more than 65 per cent, of indigo-blue, with not less than 15 per cent, of ash. Indigo is tasteless, odorless, and of an intense blue color, passing into purple. INDIGO BIRD, a North American bird of the finch family, a native of the United States, as far N. as the Missouri, which it visits in summer, and of Central America, where it spends the winter. It is about 5% inches in length, of a beautiful blue color. INDIGO GREEN, a green obtained from indigo by adding potash to an alco- holic solution of an alkaline hyposul- phate of indigo. INDIGO-RED, one of the coloring mat- ters found in commercial indigo. It may be obtained by exhausting indigo with hydrochloric sulphuric acid then with a strong caustic alkaline lye. Indigo-red may also be obtained from the fresh leaves of Polygonum tinctoritim. INDIGO-WHITE, in chemistry, CeHi^- NlO~., a white powder introduced by the action of reducing agents on pure indigo- blue. It may be prepared by digesting for 24 hours a mixtui'e of indigotine, hy-
