CHROMATYPE-CHROME.

CHROMATYPE, kro'ma-tip [Gr. chrome, color; typos, impression]: photographic process, and its result, thus described by its discoverer, R. Hunt. One drachm of suiphate of copper is dissolved in one ounce of distilled water, to which is added half an ounce of a saturated solution of bichromate of potash; this solution is applied to the surface of the paper, and when dry, it is fit for use, and may be kept for any length of time without spoiling. When exposed to sunshine, the first change is to a dull brown, and if checked in this stage of the process, a negative picture results; but if the action of light is continued, [ the browning gives way, and a positive yellow picture on a white-ground is obtained. In either case, if the paper, when removed from sunshine, is washed over with a solu- · tion of nitrate of silver, a very beautiful positive picture results. In practice, it will be found advantageous to allow the bleaching action to go on, to some extent; the picture resulting from this will be clearer and more defined than that obtained when the action is checked at the brown stage. To fix these pictures, it is necessary to remove the nitrate of silver, which is done by washing them in pure water. If the water contains any chlorides, the picture suffers, and long soaking in such water obliterates it-or if a few grains of common salt be added, the apparent destruction is rapid. The picture is, however, capable of restoration, all that is necessary being to expose it to sunshine for a quarter of an hour, when it revives; but instead of being of a red color, it assumes a lilac tint, the shades of color depending upon the quantity of salt used to decompose the chromate of silver which forms the shadow parts of the picture. The substitution of sulphate of nickel for sulphate of copper, has been suggested as yielding a higher degree of sensitiveness and greater definition. Neither process has been much used.

CHROME, n. krōm, or CHROMIUM, n. krō' mi-ŭm [Gr. chrōma, color]: one of the metals, so named from the bright colors of its salts. It was discovered by Vauquelin, 1797. C. occurs naturally as the chromate of lead (PbO,CrO3); and as the chromite of iron, chrome iron ore or chromic iron (FeO, Cr2O3), found usually in mass, sometimes crystallized in octahedrons, at Unst and Fetlar in the Shetlands, Portsoy in Banffshire, France; and also in Maryland, Pennsylvania, etc. The metal has been obtained in powder and in scales, but as a metal it possesses no interest. The principal compound of C. is the bichromate of potash, obtained by heating chrome-iron ore in powder with onefourth of its weight of nitre, and then digesting in water, which dissolves out the chromate of potash (KO,CrO3), a yellow salt, and when this is acted upon by sulphuric acid, it is converted into bichromate of potash (KO,2CrOs), readily crystallizes in orange-red crystals, which is soluble in water, and is largely used by the dyer and calico-printer. If this salt be added to a solution of lead, an abundant yellow precipitate occurs of chromate of lead (PbO,CrO,), or chrome yellow, used largely by the painter as a yellow pigment. A sesquioxide of C. (Cr2O1), chrome

CHROMIC ACID-CHRONIC.

green, has a bright green color, useful in enamel-painting, and being innocuous, it is now introduced into paperhangings instead of the highly dangerous arsenical green pigment. The bichromate of potash is used in conjunction with sulphuric acid as an agent in bleaching palm-oil and other oils and fats. CHROMIC, a. krō'mik, of or from chrome. CHROMATE, n. krō'māt, a compound of chromic acid with a base: CHROMATISM, n. krō'mă-tizm, and CHROMIsи, n. krō mizm, in bot., an abnormal or unnatural coloring of plants: CHROME-OCHRE, -ō'kr, oxide of chrome of a fine yellowish green: CHROMITE, n. krō'mit, or CHROMATE OF IRON, OF CHOME-IRON ORE (see above).

CHROMIC ACID: a combination of chromium trioxide and water; chemical formula, HCrO4. It is a red crystalline solid of powerful oxidizing properties; soluble in water, alcohol, and ether. Its solution in alcohol undergoes decomposition when heated or exposed to light, setting the alcohol on fire. It is used as a substitute for nitric acid in etching processes, in electric batteries, and as a basis for colors; and in surgery as a caustic.

CHROMIC IRON: syn. Chromite; a mineral composed principally of oxides of iron and chromium: see CHROME. One typical analysis gives iron protoxide 32%, chromium sesquioxide 68%. Some of the chromium is generally replaced by aluminium and some of the iron by the same or by magnesium. Its color is black or brownish-black; without cleavage; its crystals are octahedral; it is attracted by magnet. It is extensively mined in California and Scotland, as an ore of chromium. Hardness 5'5. Specific gravity, 4.32-46.

CHROMOGEN, n. krō'mō-jěn [Gr. chroma, color; gennão, I produce]: in bot., the coloring matter of petals; any other coloring matter but green; also, in same sense, CHROMULE, n. krō'mül [Gr. ulē, matter].

CHROMO-LITHOGRAPH, n. krō'mō-lith'ō-graf, colloq., CHROMO [Gr. chroma, color; Eng. lithograph]: lithograph printed in colors. CHROMO-LITHOGRAPHY, the art of printing in colors: see LITHOGRAPHY. CHROMO-PHOTOGRAPHY [see PHOTOGRAPHY]: the art of producing photographs in their natural colors. CHROMO-XYLOGRAPH, n. -zil ō-graf [Gr. rulon, wood, cut-wood]: a wood-engraving printed in colors instead of black from an ordinary block: see under XYLO.

CHROMOSPHERE, n. krō'mō-sfër [Gr. chroma, color; sphaira, a sphere]: the outer cloudy envelope around the sun through which the light of the photosphere must pass.

CHROMULE, n. krō'mul [Gr. chroma, color; hui, matter]: any coloring matter other than green; the coloring matter of petals: see EXTRACTS.

CHRONIC, a. kronik, or CHRONICAL, a. --kål [Gr. chronikos; F. chronique --from Gr. chronos time, duration]: continuing a long time, as a disease; the opposite of acute. CHRONICLE, n. kroni-kl, history; specially. history in

CHRONICLES.

which events are treated in the order of time. A C. is understood to differ from annals in being more connected and full, the latter merely recording individual occurrences under the successive years or other dates. Most of the older histories were called chronicles, such as the Saxon Chronicle, Holinshed's Chronicle. The term is applied seldom to a modern book, but frequently to a newspaper-for instance, The Morning Chronicle. V. to record events in the order of time; to record or register. CHRONICLING, imp. kròn'ikling. CHRONICLED, pp. krŏn'í-kld, recorded or registered. CHRONICLER, n. -kler, one who; a historian.

CHRONICLES, FIRST AND SECOND BOOKS OF: in the Hebrew canon of the Scriptures, a single book called Events of the Times. In the Septuagint this was divided into two, and entitled Paraleipomena (Things Omitted). This name was of dubious propriety, as the book is not a mere supplement to others. Jerome suggested Chronicon. The authorship is uncertain. Jewish and Christian tradition ascribes the work to Ezra; but internal evidence argues a later date. E.g., the passage 1 Chron. iii. 19-24 appears to reckon six generations of the descendants of Zerubbabel, whereof Ezra (viii. 2) seems to have been contemporary with the fourth. Ewald supposes the compiler to have been one of the guild of singers, in whose mind the conception of Israel as a nation had contracted to that of Jerusalem and the temple-worship; his view is still theocratic, but municipal, ecclesiastical, liturgical. This was perhaps natural after the long captivity; it was nearly inevitable after the cessation of prophecy. The book of Kings is written in the prophetic spirit; in C. that spirit is absent, and the history is looked at with the eyes of one occupied by temple-functions; and believing that Jehovah is especially if not exclusively present therein. In the books of Samuel and Kings the interests of Providence and of humanity are not localized to this extent; so they contain (from this later view-point) much that is irrelevant or unimportant, and lack much that is of value-as in laying so little stress on the history of the ordinances of worship. The comparatively secular matter seems slurred over or omitted. Such appears to be the spirit and intent of C.; at the same time, the charges of distortion, invention, and consequent general worthlessness, brought by De Wette and the rationalists, are dismissed or refuted by the best recent critics. The writer simply availed himself of the license of selection, arrangement, and col. oring common to all ancient historians, alike sacred and secular. His main source was an extensive work now lost, variously styled Book of the Kings of Israel and Judah,' 'Book of the Kings of Judah and Israel,'' Book of the Kings of Israel,' and Affairs of the Kings of Israel.' This is cited some ten times in C., and was apparently used also in preparing the canonical book of Kings, which, however, employed other materials not known to C. C. begins with Adam, and gives nine chapters to the genealogies; here, as elsewhere, these convey statistics in the form of a narrative, the names of individuals sometimes standing

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CHRONOGRAM-CHRONOGRAPH.

for branches of a family. Nothing else is retained of the earlier history, the times preceding David's reign affording little to the compiler's purpose. In the account of David and Solomon he pursues a course parallel with Samuel and Kings, but omits many items of personal interest as not bearing on his main theme. In the later annals he neglects the ten tribes, and discusses the affairs of Judah with a view to edification, striving to justify and make prominent God's ways with men in rewarding the good and punishing the rebellious. The writer is a preacher quite as much as a chronicler. His additions to the earlier records deal chiefly with events which serve his purpose of enforcing obedience, or with feasts, appointments of the temple, and Levitical archæology. He ends abruptly with the proclamation of Cyrus to rebuild the temple, and that is left to be continued in the book of Ezra. In general he seems to have followed his sources closely, and when he varies from earlier annals, as in a higher estimate of the numbers of Israel (1 Chron. xxi. 5, cf. 2 Sam. xxiv. 24), he conforms to later usage, and doubtless to accounts that lay before him. Thus his much-disputed account of the captivity and repentance of Manasseh is referred (2 Chron. xxxiii. 18) to the book of the Kings of Israel,' and derives support from some Assyrian inscriptions. We have in C. a far narrower view than in some other Old Testament books of the scope of the divine will and the mission of Israel, but there is no reason to distrust the writer's good faith. The many textual and historical difficulties presented by C., of which Jerome complained, have been but partially solved. Keil (1870) and Zöckler (1874) have written commentaries on C.; the best is that of Bertheau (1854, trans. 1857).

CHRONOGRAM, n. kron'ŏ-grăm, or CHRONOGRAPH [Gr. chronos, time; gramma, a writing]: whimsical device of the later Romans, resuscitated during the renaissance period, by which a date is given by selecting certain letters among those which form an inscription, and printing them larger than the others. The following C., was made from the name of George Villiers, first Duke of Buckingham: GEORGIVS. DVX. BVCKINGAMIÆ.

The date MDCXVVVIII (1628) is that of the year in which the duke was murdered by Felton, at Portsmouth. Sce Hilton's Chronograms (1882). CHRON OGRAMMATIC, a. -matik, or CHRON ́OGRAMMATICAL, a. -i-kál. CHRON'OGRAMMATICALLY. ad. -li. CHRONOGRAM MATIST, -mă-tist, a writer of.

a.

CHRONOGRAPH, n. kròn'ò grăf [Gr. chronos, time; grapho, I write], (sometimes used with the same meaning as Chronogram, q.v.): instrument for recording the precise time of an occurrence. A stop-watch is a kind of C

Benson's C. is intended to measure intervals of time down to tenths of a second, for use at horse-races and other occasions where a seconds watch is not exactly suited. It has an ordinary quick train lever movement, carrying hands which move over a dial. One of these is a seconds hand,

CHRONOGRAPH.

very peculiarly made, being double, consisting of two distinct hands, one superposed on the other. The outer end of the lower-most hand has a small cup with a minute hole at the bottom; while the corresponding end of the uppermost hand is bent over so as exactly to reach this puncture. The little cup is filled with ink, having a consistency between that of writing fluid and printers' ink. Suppose that a horse-race is about to take place. The observer keeps a steady look-out for the fall of the starter's flag, or whatever the signal may be; he gives a pull to a cord or string connected with the mechanism peculiar to the instrument; by this movement, the outer and bent end of the upper seconds hand dips down through the ink-cup in the lower hand, and through the puncture to the dial. A small black spot or mark is thus made upon the dial-plate; and this is repeated as each horse passes the winning-post. A record may thus be obtained to about a tenth of a second.

Strange's C. for a more scientific purpose, is constructed with more careful details. The object is to measure extremely short intervals of time, for the determination of longitudes in great trigonometrical surveys. The observer, when a particular star traverses the field of his telescope, touches a small ivory key; and on the instant, a dot or mark appears on a sheet of paper coiled round a cylinder. The instrument being connected with an astronomical clock, there is a dot made for every beat of the pendulum; and as these dots are a considerable space apart (considera. ble, that is, for the refined instruments of the present day), it is possible to determine so wonderfully minute an interval as one hundredth of a second.

In the very elaborate galvanic chronographs made by the Messrs. Dent, for astronomical purposes, the lapse of every second in the minute, save the 60th, is pricked on a cylinder covered with paper; and the touching of a stud by an observer causes an observation-pricker also to punct ure the cylinder. By measuring the relation of the latter mark to the preceding one, the time can calculated to the Tth of a second, and the record is kept for reference. (See description in Nature, vol. xxiii.)

A recording C. was designed by Prof. C. A. Young, 1866, to mark the instant of observation in hours, minutes, seconds, and hundredths of a second, in printed characters, and in a form suitable for preservation and reduction.

The

Chronographs connected with electric and magnetic apparatus are used for determining the velocity of projectiles. Many forms have been devised by Noble, Bashforth, Navez, Le Bouleugé, and other inventors. general arrangement consists in causing the bullet to pass through a series of screens: the rupture of each screen breaks for a moment the continuity of an electric current, sets in action an electro-magnetic apparatus, and makes a permanent mark or record. CHRONOGRAPHER, n. -răfer, a chronologist.