Page:EB1911 - Volume 05.djvu/288

Table of Surface-Tension at 20° C. (Quincke).

Liquid.	Specific Gravity.	Tension of surface separating the liquid from			Angle of contact with glass in presence of
		Air.	Water.	Mercury.	Air.	Water.	Mercury.
Water	1	81	· ·	418	25° 32′	· ·	25° 6′
Mercury	13.5432	540	418	· ·	51° 8′	26° 8′	· ·
Bisulfuride of Carbon	1.2687	32.1	41.75	372.5	32° 16′	15° 8′	· ·
Chloroform	1.4878	30.6	29.5	399	· ·	· ·	· ·
Alcohol	0.7906	25.5	· ·	399	25° 12′	· ·	· ·
Olive Oil	0.9136	36.9	20.56	335	21° 50′	17°	47° 2′
Turpentine	0.8867	29.7	11.55	250.5	37° 44′	37° 44′	47° 2′
Petroleum	0.7977	31.7	27.8	284	36° 20′	42° 46′	· ·
Hydrochloric Acid	1.1	70.1	· ·	377	· ·	42° 46′	· ·
Solution of Hyposulphite of Soda	1.1248	77.5	· ·	442.5	23° 20′	· ·	10° 42′

Olive Oil and Alcohol, 12.2.
Olive oil and aqueous alcohol (sp. g. .9231, tension of free surface 25.5), 6.8, angle 87° 48′.

Quincke has determined the surface-tension of a great many substances near their point of fusion or solidification. His method was that of observing the form of a large drop standing on a plane surface. If K is the height of the flat surface of the drop, and k that of the point where its tangent plane is vertical, then

${\mbox{T}}={\tfrac {1}{2}}({\mbox{K}}-k)^{2}g\rho$

Quincke finds that for several series of substances the surface-tension is nearly proportional to the density, so that if we call $({\mbox{K}}-k)^{2}g\rho$ the specific cohesion, we may state the general results of his experiments as follows:—

Surface-Tensions of Liquids at their Point of Solidification.
From Quincke.

Substance.	Temperature of Solidification.	Surface- Tension.
Platinum	2000° C.	1658
Gold	1200°	983
Zinc	360°	860
Tin	230°	587
Mercury	−40°	577
Lead	330°	448
Silver	1000°	419
Bismuth	265°	382
Potassium	58°	364
Sodium	90°	253
Antimony	432°	244
Borax	1000°	212
Carbonate of Soda	1000°	206
Chloride of Sodium	· ·	114
Water	0°	86.2
Selenium	217°	70.4
Sulphur	111°	41.3
Phosphorus	43°	41.1
Wax	68°	33.4

The bromides and iodides have a specific cohesion about half that of mercury. The nitrates, chlorides, sugars and fats, as also the metals lead, bismuth and antimony, have a specific cohesion nearly equal to that of mercury. Water, the carbonates and sulphates, and probably phosphates, and the metals platinum, gold, silver, cadmium, tin and copper have a specific cohesion double that of mercury. Zinc, iron and palladium, three times that of mercury, and sodium, six times that of mercury.

Relation of Surface-tension to Temperature

It appears from the experiments of Brunner and of Wolf on the ascent of water in tubes that at the temperature $t^{\circ }$ centigrade

${\mbox{T}}$	$=75.20(1-0.00187t)$ (Brunner);
	$=76.08(1-0.002t+0.00000415t^{2})$, for a tube .02346 cm. diameter (Wolf);
	$=77.34(1-0.00181t)$, for a tube .03098 cm. diameter (Wolf).

Lord Kelvin has applied the principles of Thermodynamics to determine the thermal effects of increasing or diminishing the area of the free surface of a liquid, and has shown that in order to keep the temperature constant while the area of the surface increases by unity, an amount of heat must be supplied to the liquid which is dynamically equivalent to the product of the absolute temperature into the decrement of the surface-tension per degree of temperature. We may call this the latent heat of surface-extension.

It appears from the experiments of C. Brunner and C. J. E. Wolf that at ordinary temperatures the latent heat of extension of the surface of water is dynamically equivalent to about half the mechanical work done in producing the surface-extension.

References.—Further information on some of the matters discussed above will be found in Lord Rayleigh’s Collected Scientific Papers (1901). In its full extension the subject of capillarity is very wide. Reference may be made to A.W. Reinold and Sir A. W. Rücker (Phil. Trans. 1886, p. 627); Sir W. Ramsay and J. Shields (Zeitschr. physik. Chem. 1893, 12, p. 433); and on the theoretical side, see papers by Josiah Willard Gibbs; R. Eötvös (Wied. Ann., 1886, 27, p. 452); J.D. Van der Waals, G. Bakker and other writers of the Dutch school. (J. C. M.; R.) 

CAPISTRANO, GIOVANNI DI (1386–1456), Italian friar, theologian and inquisitor, was born in the little village of Capistrano in the Abruzzi, of a family which had come to Italy with the Angevins. He lived at first a wholly secular life, married, and became a successful magistrate; he took part in the continual struggles of the small Italian states in such a way as to compromise himself. During his captivity he was practically ruined and lost his young wife. He then in despair entered the Franciscan order and at once gave himself up to the most rigorous asceticism, violently defending the ideal of strict observance. He was charged with various missions by the popes Eugenius IV. and Nicholas V., in which he acquitted himself with implacable violence. As legate or inquisitor he persecuted the last Fraticelli of Ferrara, the Jesuati of Venice, the Jews of Sicily, Moldavia and Poland, and, above all, the Hussites of Germany, Hungary and Bohemia; his aim in the last case was to make conferences impossible between the representatives of Rome and the Bohemians, for every attempt at conciliation seemed to him to be conniving at heresy. Finally, after the taking of Constantinople, he succeeded in gathering troops together for a crusade against the Turks (1455), which at least helped to raise the siege of Belgrade, which was being blockaded by Mahommed II. He died shortly afterwards (October 23, 1456), and was canonized in 1690. Capistrano, in spite of this restless life, found time to work both in the lifetime of his master St Bernardino of Siena and after, at the reform of the order of the minor Franciscans, and to uphold both in his writings and his speeches the most advanced theories upon the papal supremacy as opposed to that of the councils.

See E. Jacob, Johannes von Capistrano, vol. i.: “Das Leben und Wirken Capistrans;” vol. ii.: “Die handschriftlichen Aufzeichnungen von Reden und Tractaten Capistrans,” (1st series, Breslau, 1903–1905). (P. A.) 

CAPITAL (Lat. caput, head), in architecture, the crowning member of the column, which projects on each side as it rises, in order to support the abacus and unite the square form of the latter with the circular shaft. The bulk of the capital may either be convex, as in the Doric capital; concave, as in the bell of the Corinthian capital; or bracketed out, as in the Ionic capital. These are the three principal types on which all capitals are based. The capitals of Greek, Doric, Ionic and Corinthian orders are given in the article Order.

From the prominent position it occupies in all monumental buildings, it has always been the favourite feature selected for ornamentation, and consequently it has become the clearest indicator of any style.

The two earliest capitals of importance are those which are based on the lotus (fig. 1) and papyrus (fig. 2) plants respectively, and these, with the palm tree capital, were the chief types employed by the Egyptians down to the 3rd century B.C., when,