CIRCLE-CIRCUIT.

wire by a touch of the micrometer screw-head. The circle being now clamped (or made fast), the 'reading' is determined as before by reading the pointer and microscopes, and adding or subtracting, as the case may be, the reading of the micrometer. This reading now subtracted from the zenithreading gives the meridian zenith distance of the star; and this, again, subtracted from 90 ̊, gives its meridian altitude above the horizon.

At the royal observatory (q.v.) of Greenwich, the principal observations are now made by an instrument which. combines the mural C. with the transit instrument: see TRANSIT INSTRUMENT.

CIRCLE. QUADRATURE OF: see QUADRATURE.
CIRCLES OF THE
SPHERE, under ARMILLA.

SPHERE: see ARMILLARY

CIRCLEVILLE, sér kl-vil: city and capital of Pickaway co., 0., on the Scioto river, and the Ohio canal, 25 m. s. of Columbus by the Scioto Valley railroad, 104 m. e.n.e. of Cincinnati by the Cincinnati and Muskingum Valley railroad. It was founded 1810 on the site of an aboriginal circular fort, which was surrounded by two walls 20 ft. high, with a ditch between; close by was a square fortification with sides 55 rods in length. Camp Charlotte, where Lord Dunmore made a treaty with the Indians 1774, was 7 m. s.e. and Logan's famous speech was made 4 m. south. C. has some 14 churches, 18 schools, 3 newspapers, 3 banks, several building and loan associations, and a number of mills and factories. It is the centre of a rich farming region, and a market for broom corn, which is largely raised in the neighborhood. Pop. (1880) 6,046; (1890) 6,556.

CIRCUIT, n. ser-kit [F. circuit-from L. circuitus, a going round in a circle-from L. circum, round; itum, to go]: the act of moving or passing round; the space inclosed by a circle; a ring; the journey of British judges in holding courts in different parts of a country; the tract of country so visited. England and Wales, with the exception of the county of Middlesex, are divided for judicial purposes, into seven circuits, which the judges of the high court of justice visit four times a year in pairs for the purpose of adjudging civil and criminal causes. The number of circuits was reduced from eight to seven by authority of the judicature act, 1875. They are-the Northern, Northeastern, Midland, South-eastern, Oxford, Western, and North and South Wales. Trials by jury of issues of fact within London and Middlesex are held at what are called the London and Middlesex sittings Criminal charges within that and surrounding districts are disposed of at sessions held monthly at the central criminal court. 'These judges of assize came into use in the room of the ancient justices of eyre, justiciarii in itinere, who were regularly established, if not first appointed, by the parliament of Northampton, A.D. 1176, in the twenty-second year of Henry II., with a delegated power from the king's great count, or aula regia, being looked upon as members thereof.'Stephen's Com., iii, 415. See ASSIZE and NISI PRIUS.IRELAND is divided into the Northeast, the Northwest, the

CIRCUIT COURT-CIRCULAR NOTES.

Home, the Leinster, Connaught, and Munster circuits. For the Scottish circuits, see JUSTICIARY COURT. CIRCUIT, v. to move in a circle; to go round. CIRCUITOUS, a. -kū'itus, going round in a circle; not straight or direct. CIRCU'ITOUSLY, ad. -li. TO MAKE A CIRCUIT, to go round.

CIRCUIT COURT: next in rank to the United States supreme court. There are nine circuits, each consisting of several states, and each is allotted to one of the nine justices of the supreme court, who must attend at least one term of court in each district of his circuit every two years. A special circuit judge also is appointed and resident in each circuit. Courts are held by either of these, or by the two together, or by a district judge alone or sitting with either of them. Courts may be held at the same time in different districts of the same circuit. These courts have original jurisdiction, concurrently with those of the states, in civil suits in law or equity for more than $500 between citizens of different states, or where an alien is a party or the United States plaintiff, as well as in revenue cases and some in bankruptcy, and in some criminal cases concerning persons denied citizenship under state laws, or offenses against the United States. Their appellate jurisdiction extends to admiralty and maritime cases, to civil actions referred from the dist. courts, to patent cases, and some others. Several states have circuit courts of their own.

CIRCULAR, a. sér kū-ler [L. circulus, a circle (see CIRCLE]: pertaining to a circle, or in the form of a circle; round; ending in itself; addressed to a number or circle of persons: N. a written or printed letter or note sent to a number or circle of persons. CIR'CULARLY, ad. -li, in a circular manner; ending in itself. CIRCULARITY, n. sẻr'kūlari-ti, a circular form or character. CIR'CULATE, v. -lāt [L. circulatus, spread or gathered in a circle]: to spread or move in a circle; to spread; to pass from one place or person to another; to be diffused: N. a recurring or repeating decimal or part of a decimal. CIRCULATING, imp.: ADJ. moving or passing round; repeating; diffusing; current, or that constitutes currency. CIR'CULATED, pp. ČIR'CULATOR, n. one who. CIRCULATION, n. -la'shun, the act of moving round; a series repeated in the same order; the act of going and returning; currency of money. CIRCULAR NOTES, series of notes for various amounts, payable on demand, issued by a banker for the convenience of travellers in other countries, which may be cashed at many places as money is required. SYN. of circulate. v.': to propagate; spread; disseminate; diffuse.

CIRCULAR NOTES: bank-notes specially adapted for the use of travellers in foreign countries; and being, in fact, bills personal to the bearer, they are believed to be more safe as travelling money than ordinary notes or coin. C. N. are furnished by the chief banking-houses. Those who wish to obtain them determine beforehand what sum of money they will require on their journey, and that they pay to the banker, who, in exchange, gives C. N. to the amount, the series of notes being of varying values. With these notes is given a letter of indication.' This letter

CIRCULAR NUMBERS-CIRCULATING LIBRARY. is addressed to foreign bankers, requesting them to pay the notes presented by the bearer, whom they name, and to aid him in any way in their power. By way of verification, the bearer appends his signature, and the letter is complete. On the back of the letter there is a long list of foreign bankers, extending all over Europe, any of whom will cash one or more of the C. N. on being presented and indorsed by the bearer; the indorsement being of course compared with the signature on the letter of indication, which is at the same time exhibited by the traveller. In paying these notes, the money of the country is given, according to the course of exchange, and free of any charge for commission. For security in case of theft or loss the letter and the notes should not be carried together. These C. N. are doubtless a safe and convenient species of money, exchangeable in almost every town visited; and if any remain over on coming home, they will be taken back at their value by the banker who issued them. There are, however, certain drawbacks connected with these notes. In many instances, there is a difficulty in finding the banker named; for foreign bankers generally occupy obscure apartments several stories high, and often in dingy out-of-the-way alleys. To discover them, a commissionaire may be necessary. Then, in some instances, it happens that the banker jealously scrutinizes the bearer, asks to see his passport, and takes a note of the hotel at which he lodges; all which proper precautions against roguery are disagreeable to some persons. Further, the C. N. are ordinarily of a thick stiff paper, which does not well fit into a purse or pocketbook On these accounts, the careful class of British tourists who expect to keep to the main thoroughfares of France, Germany, and Belgium, often prefer English banknotes or gold coin. See CREDIT, LETTERS OF.

CIRCULAR NUMBERS: numbers whose powers end on the same figure as they do themselves; such are numbers ending in 0, 1, 5, 6.

CIRCULAR PARTS: name given to a rule in spherical trigonometry, invented by Lord Napier.

CIRCULATING DECIMALS: see DECIMALS.

CIRCULATING LIBRARY: collection of books lent out on hire-circulated from hand to hand. The plan of lending books on hire is not new. Chevillier, in his Originis de l'Imprimerie de Paris (4to, 1694), mentions that, in 1342, a century before the invention of printing, a law was framed in Paris to compel stationers to keep books to be lent on hire, for the special benefit of poor students and others: see E. S. Merryweather's entertaining work, Bibliomania in the Middle Ages (London, 1849); which mentions such libraries in the middle ages at Paris, Toulouse, Vienna, and other places. This writer, quoting from Chevillier, gives a list of books so lent out, with the prices for reading them. The books all are of a theological or classical kind. Among them is the Bible, the perusal of which is set down at 10 sous. This rate of charge,' it is added, was also fixed by the university, and the students borrowing these books were privileged to transcribe them, if they chose; if

CIRCULATING LIBRARY.

any of them proved imperfect or faulty they were denounced by the university, and a fine was imposed upon the bookseller who had lent out the volume.'

By whom the modern C. L. was projected, there is no record. All that can be given are a few facts on the subject. It is known that Allan Ramsay, author of The Gentle Shep herd, a bookseller in Edinburgh, established a C. L. in that city about 1725. Fond of dramatic literature, Ramsay appears to have incurred some local obloquy by lending out plays; and his wish to introduce a taste for the drama into Edinburgh may accordingly have suggested the notion of a circulating library. Be this as it may, the library which he began was continued through various hands for above a hundred years. At Ramsay's death, 1758, his library was sold to a Mr. Yair, whose widow carried it on till 1780, when it was bought by Mr. James Sibbald, an ingenious inquirer into Scottish literary antiquities. Sibbald lived some years as a literary man in London, during which period, beginning with 1793, the C. L. was carried on, subject to an agreement, by a Mr. Laurie. Sibbald afterward resumed the direction of the library, which he considerably extended. At his death, 1803, his brother attempted to carry it on; but not being successful in his management, he disposed of it in 1806 to Alexander MacKay, who by the acquisition of various other libraries, greatly enlarged the collection, under the name of the Edinburgh C. L. He retired 1831, when this extensive collection of books was broken up and sold by auction.

There are several circulating libraries in London, claiming to be of old date, but probably not so early as 1725. In a late reprint of an old advertisement, are 'Proposals for erecting a Public Circulating Library in London,' under date 1742, June 12. This library was to be established in some convenient place at or near the Royal Exchange; and the subscription was to be a guinea per annum. Two of the present circulating libraries are believed to be descended from this primitive stock. So numerous had circulating libraries become in the early years of the present century, that they absorbed whole editions of novels and romances prepared for the purpose by a London publishing establishment, designated the Minerva Press. The issue of cheap books and periodicals about 1832 (see BOOK-TRADE) seriously damaged the C. L. system. The vast increase of the reading public in recent times, and the continually augmenting number of new and popular works of a respectable class, have restored prosperity to circulating libraries, especially in London, where some of them are on a surprisingly gigantic scale. To one library alone, as many as 100,000 new books are said to be added annually, and of kinds very different from those of the old Minerva Press school For an annual subscription-usually of a guinea-a number of new books may at all times be procured, and kept for a specified period. Books no longer in demand are sold at reduced prices.

For the circulation of books among the members of private associations, see BOOK-CLUB; and for the circulation of books in rural districts by means of libraries shifted from place to place, see ITINERATING LIBRARIES.

CIRCULATION.

CIRCULATION, in Anatomy and Physiology: term used to designate the course of the blood from the heart to the most minute blood vessels (the Capillaries, q.v.), and from these back to the heart.

The subject may be considered under two divisions: I. Anatomy of the organs of circulation. II. Physiology of the circulation.

I. Anatomy of the Organs of Circulation.-The organs of C. consist of the heart, arteries, veins, and capillaries. The course of the blood through these organs will be best elucidated by the aid of a diagram, equally applicable for all other mammals as well as for man, and for birds. The

a

shaded part of fig. 1 represents structures filled with impure or venous blood, while the unshaded portion represents structures in which pure, oxygenated, arterial blood occurs. In this diagram we observe a dotted circle, representing a closed bag or sac, termed the pericardium, and inclosing the four cavities c, v, c', v', of which the heart is composed. Two of these cavities, c and c', are for the purpose of receiving the blood as it flows into the heart, and are termed the auricles; while the two cavities v and v' are for the purpose of propelling the blood through the lungs and general system respectively, and are termed the ventricles; The vessels that transport blood into the auricles are termed veins, and Fig.1.-Mode of Circula- the vessels through which the blood mammals, and in birds: is driven onward from the ventrih, heart; v, right ventricle; cles are known as arteries (q.v.). The v, left ventricle; c, right diagram further shows that what a, aorta; d, vena cava; we commonly term the heart, is in e, greater circulation; reality two distinct hearts in apposib, smaller circulation; tion with each other-one, shaded f. pulmonary artery; 9 in the figure, which is called the pulmonary veins. right, or venous, or pulmonary heart; and the other, unshaded, which is called the left, or arterial, or systemic heart-the last name having been given to it because the blood is sent from it to the general system; as the right heart is termed pulmonary from its sending blood to the lungs. We will now trace the course of the blood as indicated by the arrows in this diagram. commencing with the right auricle, c. The right auricle contracting upon the venous or impure blood with which we suppose it filled, drives its contents onward into the right ventricle v, through an opening between these two cavities, called the right auriculo-ventricular opening, which is guarded by a valve, named the tricuspid-from its being composed of three pointed membranous expansions-which almost entirely prevents the regurgitation or reflux of the blood from the ventricle into the auricle. The ventricle v being now

auricle; c' left auricle;