The pneumatic caisson used in hydraulic engi- neering consists of a steel box without a lower side, but with sides and top air-tight. It rests on the bottom, into which the sliarp edges of its sides are forced by pressure or weight. To further assist in keeping the water out, an ade(iuate air-pressure is maintained in it. The men who work in the caisson enter through airlocks which have air-tight doors on each side, so that very little pressvire is lost. See Foundation, and Dock.
CAISSON DISEASE. A rare affection in-
duced by remaining for any length of time in a
caisson. The disease was first described by Pol
and W atcUe, in 1845. The symptoms are buzzing
and pain in the ears, dizziness, loss of power in the legs. seere pain in the arms, legs, and shoulders, bleeding from the nose and lungs, and
occasionally unconsciousness. The cause of the
disease is uncertain. According to one theory,
caisson disease is due to poisoning by carbonic
acid. According to another theory, it is due to
congestion of the internal organs with subsequent blood-stasis, resulting in possible blocking of the blood-vessels by small thrombi, followed in turn by a necrotic process. Finally, according to a third theory, the disease is due to increased solution by the blood of the compressed gases of the air, (principally nitrogen and carbonic acid) and to their rapid liberation during decompression. Judging from the careful observations made in 1891 by Van Rensselaer, the second theory is probably nearest to the truth.
In the treatment of caisson disease, morpliia, heat, stimulants, strychnine, and ergot are recommended. Returning to compressed air for a time, and then emerging very slowly, has bene- fited many sufferers. Preventive treatment may consist in securing the removal of carbonic acid from the air in the caisson and increasing the time spent in "locking out' to one minute for every three pounds of pressure, a sudden transi- tion from compressed air to the pressure of the atmospliere being quite dangerous. Above all, only perfectly sound men should be selected for work in caissons. Consult: Pol and Watelle, "ilemoiie sur les effets de la compression de Pair," in Annates d'hygiine publique et de medicine legale (Paris, 1884) ; Oertel, "Hand- huch der respiratorischen Therapie," in Ziems- sen, Htindbtieh der nllgemeinen Therapie, Band 1, Theil 4 (Leipzig, 1882) ; Smith, The Physiological, Pathological, and Therapeutic Effects of Cumpref^sed Air (Detroit, Mich., 188C) : and Lloyd, "Effects of Compressed Air," in Twentieth Century Practice, VoL III. (New York, 18!}5). See FofXDATlON.
CAITHNESS, kath'nes. The northernmost
county of Siiithind. Its area is 686 square miles (Map: Scotland, El). The general aspect of
Caithness is level and bare, it being in great part moorland and destitute of trees, while the sea-coast is bold and rocky, with many bays, inlets,' promontories, and caves. The chief crops are oats, barley, turnips, and potatoes. The occuj)ants of the small farms divide their time between farming and herring, ling, cod, salmon, and lobster lishing. Wick, the county town, is the chief scat of the British herring fisherv. Population, in 1801. 22,000: in 18.51. .38.700"; in 18!J1, 37,- 177: in l!llll. :!:i.8iin.
CAITHNESS FLAGSTONE. A dark-
colored bituminous schist, slightly micaceous and calcareous, valuable on account of its toughness and durability for pavements, cisterns, and various otiier purposes. Flagstones of this material are largely exported. They belong to the Devonian Old Red Sandstone, and contain abundant remains of fossil fishes. See Devonian, and Olu Red Sandstone.
CA'IUS. The name assumed by Kent in
Shakespeare's King Lear.
CAIUS, Doctor. A French physician in Shakespeare's Merry Wives of Windsor. He is
in love with Anne Page, and eloj)es with a boy
disguised in her clothes.
CAIUS, kez, .John (1310-73), An English
physician, the co-founder of Gonville and Caius
College, Cambridge. His real name was Kay
or Kaye, which he Latinized into Caius. He was
born in Norwich, was educated at Gonville Hall,
Cambridge, and, in medicine, at tlie University
of Padua and elsewhere on the Continent, spend-
ing much time in search of accurate texts of
Galen and Hippocrates. On his return he practiced with success at Cambridge, Shrewsbury, and Norwich. In 1.547 he was elected a fellow of
the College of Physicians, of which he was afterwards nine times elected president. He also became physician to Edward VI., Queen Mary, and
Queen Elizabeth. He acquired much wealth from
the practice of his profession and employed it in the encouragement of science and learning. In
1557 he refounded Gonville Hall, thereafter
known as Gonville and Caius College. In 15.59
he was chosen master, and. although he was a
Roman Catholic, he retained the office under
Elizabeth. His books number twenty-seven titles,
including critical, antiquarian, and scientific
works, the most famous of which is .1 Bake of
Counseill Against the Sweat and Hweatyng rich-
ness ( 1552) .
CAIUS COLLEGE. See Gonville and Caius
College.
CAIUS GRACCHUS. A tragedy by J. Sheridan Knowles, published in 1815 and produced at the Belfast Theatre, on February 13 of that year. Maeready brought out a remodeled version on November 18, 1823, at Covent Garden.
CAIVANO, kt-va'no. A city in south Italy,
five miles north of Naples, with which it is connected by a street railway (Map: Italy, J 7).
The chief trade is in the grain, hemp, fruit, wine, and olives that grow in the vicinity. It was a place of considerable strength in the Middle Ages, and still retains remains of walls and towers. Population (commime), in 1881, 12,000; in 1901, 12,204.
CAIX, ka-eks'. Napoleon (1845—). An Ital-
ian philologist. He was born at Bozzolo, near
Alantua, and was educated in Cremona and Pisa.
in 18fi9 he became professor of ancient languages at the Lyceum of Parma, and in 1873 professor of Romanic languages and comparative philology at the Institute of Higher Studies, Florence. The following are some of his numerous publications: ^"U'jio sulla storia della lingua e dei dialetti d'ltulia (1872); Sulla lingua del contralto (187(5) ; Le origini delta lingua poetica italiana (1880), which work is generally considered his best.
CAJAMARCA, kii'iia-niUr'ka. .An interior
liepartijK lit nf I'liu, in the northwestern part of the republic (.Map: Peru, B .5). It has an area
