Part 42

Thus the use of the camera and of the lens with it was well known before Porta published his second edition of the _Magia Naturalis_ in 1589. In this the description of the camera obscura is in lib. xvii. cap. 6. The use of the convex lens, which is given as a great secret, in place of the concave speculum of the first edition, is not so clearly described as by Barbaro; the addition of the concave speculum is proposed for making the images larger and clearer, and also for making them erect, but no details are given. He describes some entertaining peep-show arrangements, possibly similar to Alberti's, and indicates how the dark chamber with a concave speculum can be used for observing eclipses. There is no mention whatever of a portable box or construction beyond the darkened room, nor is there in his later work, _De Refractione Optices Parte_ (1593), in which he discusses the analogy between vision and the simple dark room with an aperture, but incorrectly. Though Porta's merits were undoubtedly great, he did not invent or improve the camera obscura. His only novelty was the use of it as a peep-show; his descriptions of it are vague, but being published in a book of general reference, which became popular, he acquired credit for the invention.

The first to take up the camera obscura after Porta was Kepler, who used it in the old way for solar observations in 1600, and in his _Ad Vitellionem Paralipomena_ (1604) discusses the early problems of the passages of light through small apertures, and the rationale of the simple dark chamber. He was the first to describe an instrument fitted with a sight and paper screen for observing the diameters of the sun and moon in a dark room. In his later book, _Dioptrice_ (1611), he fully discusses refraction and the use of lenses, showing the action of the double convex lens in the camera obscura, with the principles which regulate its use and the reason of the reversal of the image. He also demonstrates how enlarged images can be produced and projected on paper by using a concave lens at a suitable distance behind the convex, as in modern telephotographic lenses. He was the first to use the term _camera obscura_, and in a letter from Sir H. Wotton written to Lord Bacon in 1620 we learn that Kepler had made himself a portable dark tent fitted with a telescope lens and used for sketching landscapes. Further, he extended the work of Maurolycus, and demonstrated the exact analogy between the eye and the camera and the arrangement by which an inverted image is produced on the retina.

In 1609 the telescope came into use, and the danger of observing the sun with it was soon discovered. In 1611 Johann Fabricius published his observations of sun-spots and describes how he and his father fell back upon the old method of projecting the sun's image in a darkened room, finding that they could observe the spots just as well as with the telescope. They do not seem to have used a lens, or thought of using the telescope for projecting an enlarged imase on Kepler's principle. This was done in 1612 by Christoph Schemer, who fully described his method of solar observation in the _Rosa Ursina_ (1630), demonstrating very clearly and practically the advantages and disadvantages of using the camera, without a lens, with a single convex lens, and with a telescopic combination of convex object-glass and concave enlarging lens, the last arrangement being mounted with an adjustable screen or tablet on an equatorial stand. Most of the earlier astronomical work was done in a darkened room, but here we first find the dark chamber constructed of wooden rods covered with cloth or paper, and used separately to screen the observing-tablet.

Various writers on optics in the 17th century discussed the principle of the simple dark chamber alone and with single or compound lenses, among them Jean Tarde (_Les Astres de Borbon_, 1623); Descartes, the pupil of Kepler (_Dioptrique_, 1637); Bettinus (_Apiaria_, 1645); A. Kircher (_Ars Magna Lucis et Umbrae_, 1646); J. Hevelius (_Selenographia_, 1647); Schott (_Magia Universalis Naturae et Artis_, 1674); C.F.M. Deschales (_Cursus, seu Mundus Mathematicus_, 1674); Z. Traber (_Nervus Opticus_, 1675), but their accounts are generally more interesting theoretically than as recording progress in the practical use and development of the instrument.

The earliest mention of the camera obscura in England is probably in Francis Bacon's _De Augmentis Scientiarum_, but it is only as an illustration of the projected images showing better on a white screen than on a black one. Sir H. Wotton's letter of 1620, already noted, was not published till 1651 (_Reliquiae Wottonianae_, p. 141), but in 1658 a description of Kepler's portable tent camera for sketching, taken from it, was published in a work called _Graphice, or the most excellent Art of Painting_, but no mention is made of Kepler. In W. Oughtred's English edition (1633) of the _Récréations mathématiques_ (1627) of Jean Leurechon ("Henry van Etten") there is a quaint description, with figures, of the simple dark chamber with aperture, and also of a sort of tent with a lens in it and the projection on an inner wall of the face of a man standing outside. The English translation of Porta's _Natural Magick_ was published in 1658.

Robert Boyle seems to have been the first to construct a box camera with lens for viewing landscapes. It is mentioned in his essay _On the Systematic or Cosmical Qualities of Things_ (ch. vi.), written about 1570, as having been made several years before and since imitated and improved. It could be extended or shortened like a telescope. At one end of it paper was stretched, and at the other a convex lens was fitted in a hole, the image being viewed through an aperture at the top of the box. Robert Hooke, who was some time Boyle's assistant, described (_Phil. Trans._, 1668, 3, p. 741) a camera lucida on the principle of the magic lantern, in which the images of illuminated and inverted objects were projected on any desired scale by means of a broad convex lens through an aperture into a room where they were viewed by the spectators. If the objects could not be inverted, another lens was used for erecting the images. From Hooke's _Posthumous Works_ (1705), p. 127, we find that in one of the Cutlerian lectures on Light delivered in 1680, he illustrated the phenomena of vision by a darkened room, or perspective box, of a peculiar pattern, the back part, with a concave white screen at the end of it, being cylindrical and capable of being moved in and out, while the fore part was conical, a double convex lens being fixed in a hole in front. The image was viewed through a large hole in the side. It was between 4 and 5 ft. long.

Johann Zahn, in his _Oculus Artificialis Teledioptricus_ (1685-1686), described and figured two forms of portable box cameras with lenses. One was a wooden box with a projecting tube in which a combination of a concave with a convex lens was fitted, for throwing an enlarged image upon the focusing screen, which in its proportions and application is very similar to our modern telephotographic objectives. The image was first thrown upon an inclined mirror and then reflected upwards to a paper screen on the top of the box. In an earlier form the image is thrown upon a vertical thin paper screen and viewed through a hole in the back of the camera. There is a great deal of practical information on lenses in connexion with the camera and other optical instruments, and the book is valuable as a repertory of early practical optics, also for the numerous references to and extracts from previous writers. An improved edition was published in 1702.

Most of the writers already noticed worked out the problems connected with the projection of images in the camera obscura more by actual practice than by calculation, but William Molyneux, of Dublin, seems to have been the first to treat them mathematically in his _Dioptrica Nova_ (1692), which was also the first work in English on the subject, and is otherwise an interesting book. He has fully discussed the optical theory of the dark chamber, with and without a lens, and its analogy to the eye, also several optical problems relating to lenses of various forms and their combinations for telescopic projection, rules for finding foci, &c. He does not, however, mention the camera obscura as an instrument in use, but in John Harris's _Lexicon Technicum_ (1704) we find that the camera obscura with the arrangement called the "scioptric ball," and known as _scioptricks_, was on sale in London, and after this must have been in common use as a sketching instrument or as a show.

Sir Isaac Newton, in his _Opticks_ (1704), explains the principle of the camera obscura with single convex lens and its analogy with vision in illustration of his seventh axiom, which aptly embodies the correct solution of Aristotle's old problem. He also made great use of the simple dark chamber for his optical experiments with prisms, &c. Joseph Priestley (1772) mentions the application of the solar microscope, both to the small and portable and the large camera obscura. Many patterns of these two forms for sketching and for viewing surrounding scenes are described in W.J.'s Gravesande's _Essai de perspective_ (1711), Robert Smith's _Compleat System of Optics_ (1738), Joseph Harris's _Treatise on Optics_ (1775), Charles Hutton's _Philosophical and Mathematical Dictionary_, and other books on optics and physics of that period. The camera obscura was first applied to photography (q.v.) probably about 1794, by Thomas Wedgwood. His experiments with Sir Humphrey Davy in endeavouring to fix the images of natural objects as seen in the camera were published in 1802 (_Journ. Roy. Inst._). (J. Wa.)

CAMERARIUS, JOACHIM (1500-1574), German classical scholar, was born at Bamberg on the 12th of April 1500. His family name was Liebhard, but he was generally called Kammermeister, previous members of his family having held the office of chamberlain (_camerarius_) to the bishops of Bamberg. He studied at Leipzig, Erfurt and Wittenberg, where he became intimate with Melanchthon. For some years he was teacher of history and Greek at the gymnasium, Nuremberg. In 1530 he was sent as deputy for Nuremberg to the diet of Augsburg, where he rendered important assistance to Melanchthon in drawing up the Confession of Augsburg. Five years later he was commissioned by Duke Ulrich of Württemberg to reorganize the university of Tübingen; and in 1541 he rendered a similar service at Leipzig, where the remainder of his life was chiefly spent. He translated into Latin Herodotus, Demosthenes, Xenophon, Homer, Theocritus, Sophocles, Lucian, Theodoretus, Nicephorus and other Greek writers. He published upwards of 150 works, including a _Catalogue of the Bishops of the Principal Sees_; _Greek Epistles_; _Accounts of his Journeys_, in Latin verse; a Commentary on Plautus; a treatise on Numismatics; _Euclid_ in Latin; and the Lives of Helius Eobanus Hessus, George of Anhalt and Philip Melanchthon. His _Epistolae Familiares_ (published after his death) are a valuable contribution to the history of his time. He played an important part in the Reformation movement, and his advice was frequently sought by leading men. In 1535 he entered into a correspondence with Francis I. as to the possibility of a reconciliation between the Catholic and Protestant creeds; and in 1568 Maximilian II. sent for him to Vienna to consult him on the same subject. He died at Leipzig on the 17th of April 1574.

See article by A. Horawitz in _Allgemeine deutsche Biographie_; C. Bursian, _Die Geschichte der klassischen Philologie in Deutschland_ (1883); J.E. Sandys, _Hist. Class. Schol._ (ed. 1908), ii. 266.

CAMERARIUS, JOACHIM (1534-1598), German botanist and physician, son of the classical scholar of the same name, was born at Nuremberg on the 6th of November 1534. After finishing his studies in Germany he visited Italy, where he graduated as doctor of medicine. On his return he was invited to reside at the courts of several princes, but preferred to settle in his native town of Nuremberg, where he had a botanical garden and formed extensive collections. He wrote a _Hortus Medicus_ (1588) and several other works. He died at Nuremberg on the 11th of October 1598.

CAMERARIUS, RUDOLF JAKOB (1665-1721), German botanist and physician, was born at Tübingen on the 12th of February 1665, and became professor of medicine and director of the botanical gardens at Tübingen in 1687. He died at Tübingen on the 11th of September 1721. He is chiefly known for his investigations on the reproductive organs of plants (_De sexu plantarum epistola_, 1694).

CAMERINO (anc. _Camerinum_), a city and episcopal see (since 465, if not sooner; Treia is now combined with it) of the Marches, Italy, in the province of Macerata, 6 m. S. of the railway station of Castelraimondo (to which there is an electric tramway) which is 24 m. W. of Macerata; 2148 ft. above sea-level. Pop. (1901) of town, 4005; of commune, 12,083. The cathedral is modern, the older building having fallen in 1799; the church of S. Venanzio suffered similarly, but preserves a portal of the 15th century. The citadel, perhaps constructed from the plans of Leonardo da Vinci, dates from 1503. Camerino occupies the site of the ancient Camerinum, the inhabitants of which (_Camertes Umbri_) became allies of the Romans in 310 B.C. (at the time of the attack on the Etruscans in the Ciminian Forest). On the other hand, the [Greek: Kamertioi] referred to in the history of the year 295 B.C. are probably the inhabitants of Clusium. Later it appears as a dependent autonomous community with the _foedus aequum_ (Mommsen, _Röm. Staatsrecht_, iii. 664). Two cohorts of Camertes fought with distinction under Marius against the Cimbri. It was much affected by the conspiracy of Catiline, and is frequently mentioned in the Civil Wars; under the empire it was a _municipium_. It belonged to ancient Umbria, but was on the borders of Picenum. No ancient buildings are visible, the Roman level lying as much as 30 ft. below the modern.

See P. Savini, _Storia delta Città di Camerino_ (2nd ed., Camerino, 1895); M. Mariani, _Intorno agli antichi Camerti Umbri_ (Camerino, 1900). (T. As.)

CAMERON, JOHN (1579-1623), Scottish theologian, was born at Glasgow about 1579, and received his early education in his native city. After having taught Greek in the university for twelve months, he removed to Bordeaux, where he was soon appointed a regent in the college of Bergerac. He did not remain long at Bordeaux, but accepted the offer of a chair of philosophy at Sedan, where he passed two years. He then returned to Bordeaux, and in the beginning of 1604 he was nominated one of the students of divinity who were maintained at the expense of the church, and who for the period of four years were at liberty to prosecute their studies in any Protestant seminary. During this period he acted as tutor to the two sons of Calignon, chancellor of Navarre. They spent one year at Paris, and two at Geneva, whence they removed to Heidelberg. In this university, on the 4th of April 1608, he gave a public proof of his ability by maintaining a series of theses, _De triplici Dei cum Homine Foedere_, which were printed among his works. The same year he was recalled to Bordeaux, where he was appointed the colleague of Dr Primrose; and when Francis Gomarus was removed to Leiden, Cameron, in 1618, was appointed professor of divinity at Saumur, the principal seminary of the French Protestants.

In 1620 the progress of the civil troubles in France obliged Cameron to seek refuge for himself and family in England. For a short time he read private lectures on divinity in London; and in 1622 the king appointed him principal of the university of Glasgow in the room of Robert Boyd, who had been removed from his office in consequence of his adherence to Presbyterianism. Cameron was prepared to accept Episcopacy, and was cordially disliked for his adherence to the doctrine of passive obedience. He resigned his office in less than a year.

He returned to France, and lived at Saumur. After an interval of a year he was appointed professor of divinity at Montauban. The country was still torn by civil and religious dissensions; and Cameron excited the indignation of the more strenuous adherents of his own party. He withdrew to the neighbouring town of Moissac; but he soon returned to Montauban, and a few days afterwards he died at the age of about forty-six. Cameron left by his first wife several children, whose maintenance was undertaken by the Protestant churches in France. All his works were published after his death.

His name has a distinct place in the development of Calvinistic theology in Europe. He and his followers maintained that the will of man is determined by the practical judgment of the mind; that the cause of men's doing good or evil proceeds from the knowledge which God infuses into them; and that God does not move the will physically, but only morally, by virtue of its dependence on the judgment of the mind. This peculiar doctrine of grace and free-will was adopted by Amyraut, Cappel, Bochart, Daillé and others of the more learned among the Reformed ministers, who dissented from Calvin's. The Cameronites (not to be confused with the Scottish sect called Cameronians) are moderate Calvinists, and approach to the opinion of the Arminians. They are also called Universalists, as holding the universal reference of Christ's death, and sometimes Amyraldists. The rigid adherents to the synod of Dort accused them of Pelagianism, and even of Manichaeism, and the controversy between the parties was carried on with great zeal; yet the whole question between them was only, whether the will of man is determined by the immediate action of God upon it, or by the intervention of a knowledge which God impresses on the mind.

CAMERON, RICHARD (1648?-1680), founder of a Scottish religious sect of Cameronians, which formed the nucleus of the regiment of this name in the British army, was born at Falkland in the county of Fife. He was educated at the village school, and his success was so great that, while still a youth, he was appointed schoolmaster. In this situation he became acquainted with some of the more enthusiastic field-preachers. Persuaded by them he resigned his post and entered the family of Sir Walter Scott of Harden as chaplain and tutor. Refusing to acknowledge the Indulgence, he joined the ranks of the non-conforming ministers, and incited the inhabitants of the southern counties of Scotland to protest openly against the new edict. So formidable was the agitation that the government pronounced illegal all armed assemblages for religious purposes. Cameron took refuge in Holland, where he resided for some time; but in the autumn of 1679 (probably) he returned to Scotland, and once more made himself formidable to the government. Shortly after the defeat of the Covenanters at Bothwell Bridge in that year, Cameron was slain in a skirmish at the Aird's, or Airs, Moss, fighting bravely at the head of the few troops which he had been able to collect. His prayer before going into battle became a tradition--"Lord spare the green and take the ripe." After the accession of William III. the survivors were amnestied, and the Cameronian regiment was formed from them.

See Andrew Lang, _History of Scotland_, vol. iii. (1907); Herzog-Hauck, _Realencyklopädie_ (1897), s.v. "Cameronianer"; A. Smellie, _Men of the Covenant_; Herkless, _Richard Cameron_; P. Walker, _Six Saints of the Covenant._

CAMERON, SIMON (1799-1889), American politician, was born in Lancaster county, Pennsylvania, on the 8th of March 1799. Left an orphan at the age of nine, he early entered journalism, and, in banking and railway enterprises, accumulated a considerable fortune. He became influential in Pennsylvania politics, and in 1845-1849 served in the United States Senate, being elected by a combination of Democratic, Whig and "American" votes to succeed James Buchanan. In 1854, having failed to secure the nomination for senator from the "Know-Nothing" Party, which he had recently joined, he became a leader of the "People's Party," as the Republican Party was at first called in Pennsylvania. In 1857 he was elected to the United States Senate as a Republican, despite a Democratic majority in the state legislature, a fact that gave rise to charges of bribery. His prominence as a candidate first for the presidential and then for the vice-presidential nomination in the Republican national convention of 1860 led to his being selected by President Lincoln as secretary of war. His administration of this office at a critical time was marked by his accustomed energy, but unfortunately also by partiality in the letting of government contracts, which brought about his resignation at Lincoln's request in January 1862 and his subsequent censure by the House of Representatives. Lincoln sent him as minister to Russia, but he returned in November 1862. He again served in the Senate (after 1872, being chairman of the committee on foreign relations) from 1867 until 1877, when he resigned to make room for his son, whose election he dictated. Cameron was one of the ablest political organizers the United States has ever known, and his long undisputed control of Pennsylvania politics was one of the most striking examples of "boss rule" in American history. The definition of an honest politician as "one who when he is bought will stay bought" has been attributed to him. He died on the 26th of June 1889.

His son JAMES DONALD CAMERON (1833- ) was born at Middletown, Pennsylvania, on the 14th of May 1833, graduated at Princeton in 1852, became actively interested in his father's banking and railway enterprises, and from 1863 to 1874 was president of the Northern Central railway. Trained in the political school of his father, he developed into an astute politician. From June 1876 to March 1877 he was secretary of war in President Grant's cabinet. In the Republican national convention of 1876 he took an influential part in preventing the nomination of James G. Elaine, and later was one of those who directed the policy of the Republicans in the struggle for the presidency between Tilden and Hayes. From 1877 until 1897 he was a member of the United States Senate, having been elected originally to succeed his father, who resigned in order to create the vacancy. He was chairman of the Republican national committee during the campaign of 1880.