59. 1803. HÆLLSTROM. Ob das Wasser in laengeren Haarroehrchen hoeher aufsteige als in kuerzern. Gilb. Ann., Vol. 14, p. 425-432. When sucking out the water from the tubes before every new trial, as supposedly was done by Musschenbrock, (see No. 21,) and Arnim (see No. 50), Haellstrom obtained conflicting results, but when avoiding it, he obtained the same height of rise whether in long or small tubes. Same conclusion was arrived at by Weitbrecht, (see No. 25.)

60. 1804. BENZENBERG. Gesetz der Cohaesion, ob es von dem der Gravitation verschieden ist, und Kritik der Murhard'schen Gruende. Gilb. Ann., Vol. 16, p. 76.

It is shown by calculation that Newton's law of gravitation sufficiently accounts for the magnitude of the cohesive force, if we only presume the attracting particles to be exceedingly small, and especially take into consideration subdivisions of their minute distances. A table is given from which it is seen, at a glance, how immensely the attractive force increases when two particles approach each other step by step from the distance of an inch down to contact, even though the force of attraction merely obeys Newton's laws of the square of the distance.

Assuming, for instance, such small distances as 36,000 billionth of an inch, and the law of gravitation prevailing, the power necessary to separate two particles, would be the same as the attractive force existing between Venus and Earth equal to 7000 billions of centners.

61. 1804. CARRADORI. Réponses aux objections du cit. Prevost. Ann. Chim., (1) Vol. 48, p. 197.

He reviews Prevost's experiments on the motion of tinfoil on water caused by ether, and other similar experiments. (See No. 42.) Maintains that even in the case of a vapor causing such a motion, this is due not to a repulsion by an elastic fluid, but simply to a surface attraction between the water and the vapors. 62. 1804. CARRADORI. Expériences et réflexions sur les apparentes répulsions entre quelques fluides, observées par Draparnaud. Ann. Chim., (1) Vol. 51, p. 217. See also Gilb. Ann., Vol. 24, p. 134, (1806).

Maintains the same point towards Draparnaud as towards Prevost, that e. g., alcohol displaces water on a porcelain dish, because of its greater attraction for the dish. Draparnaud claims that alcohol repels the water, forming thereby a continuous emission of alcohol particles towards the water finally resulting in its displacement.

63. 1805. YOUNG, THOMAS. Essay on the cohesion of fluids. Phil. Mag., Vol. 1805, p. 65.

Gives here the first complete theory of capillarity, basing it on two axioms: 1) The existence of a surface tension, equal in all directions.

2) The existence of a definite angle of contact appropriate to every combinanation of a fluid with a solid; when the fluid perfectly wets the solid, the angle is evanescent; for clean mercury and glass it is about 140°.

Thos. Young also shows how the existence of an equable surface tension may be deduced from the assumption that the equilibrium of the particles of a liquid is the result of two contending forces, one repulsive, and another cohesive. (Compare Barruel No. 47.) The essay covers such phases of capillarity as rise of liquids in tubes and between plates, relation between size of drops and height of rise, behavior of mercury, etc.

64. 1805. LAPLACE. Sur l'action capillaire, et Supplément à la théorie de l'action capillaire. Mécanique céleste, T. IV, Supplément au Xme livre.

(See Nos. 71, 76 and 77.)

65. 1806. DISPAN. Sur la prétendue attraction de surface entre l'huile et l'eau. Ann. Chim., (1) Vol. 57, p. 14-18. See also Gilb. Ann., Vol. 24, p. 184-188.

Dispan says there is no mutual attraction between oil and water: the particles of the oil are mobile; the reaction of the water forces the drop falling upon it to expand; the outer thin circle experiences friction and finally ti cohesion of the oil manifests itself and the oil gathers into a number of smaller drops. The second drop does not spread, because there is too much of an obstacle in its way; however, after a small amount of oil has become diffused, it allows succeeding drops to spread, and so on increasingly.

66. 1806. LINK, H. F. Ueber die Adhaesion tropfbarer Koerper mit einander. Gilb. Ann., Vol. 24, p. 121-128.

67.

Repeating and enlarging upon the experiments of Carradori and others, Link comes to the conclusion that the phenomena of surface attraction, contrary to Carradori's opinion, (see No. 54,) are dependent to a certain degree on chemical affinity. In support of his view, Link adduces the fact that sulfuric acid and alcohol, characterized by their marked affinity for water, repel all oils and resins from the surface of the latter. (See No. 53.)

1806.

GILBERT. Einige Streitschriften ueber die Flaechenanziehung (Adhaesion) der Fluessigkeiten unter sich und mit festen Koerpern. Gilb. Ann., Vol. 24, p. 129-188.

Gives a critical review of the polemic papers of Prevost, Venturi, Carradori, Draparnaud and Dispan. (See Nos. 40, 41, 42, 52, 53, 54, 55, 57, 61, 62 and 65.) YOUNG, THOMAS. Lectures on Natural Philosophy. London. 1807.

68.

1807.

69.

1807.

RUMFORD, B. GRAF von.

Versuche und Beobachtungen

ueber die Adhaesion der Wasserteilchen unter einander. Gilb. Ann., Vol. 25, p. 121.

Experiments by Rumford plainly demonstrate the existence of a surface film in water under ordinary conditions. Small particles of heavy substances, like a needle, or fine silver wire, or even drops of mercury will float on water when they first pass through a layer of ether; but will sink without delay upon passing through alcohol. The mercury, when floating plainly rests imbedded in a cavity, separated from the water by a thin film, which seems to be connected with the glass. Rumford finally points out that the existence of a surface tension of the water is of the utmost consequence in the economy of nature. But for the influence of that force the breeze would carry away the water particles mechanically, much more easily than sand which is so readily blown up as dust and every continuous ocean breeze would result in an inundatior.

70. 1807.

LINK, H. F. Ueber Festigkeit und Fluessigkeit. Gilb. Ann.,
Vol. 25, p. 133-146.

A liquid is characterized by the great mobility of its smallest particles, because of an almost entire absence of interior friction. Particles within the liquid are in perfect equilibrium since they are attracted (or repelled) equally on all sides by their neighboring particles. But particles composing the surface of the liquid, are attracted downward only, because there are no particles above to compensate for that downward force.

Thus the surface forms a film that is pressing against the interior of the fluid. This condition of the surface resembles the solid state, and some experiences on surface resistance (see No. 69,) strongly favor such a view. Link now argues that the solid condition consists in an interior multiplication of such surfaces, resulting in the formation of fibers and lamels. He declares the liquid condition to be the normal form of matter.

71. 1807. BIOT. On the Theory of Laplace. Reported by Gilbert. Gilb. Ann., Vol. 25, p. 233-254.

The distniguishing feature of Laplace's theory is that all explanations of capillary phenomena are derived from the shape of the liquid surface. In plain surfaces there exists a force of unknown absolute value, pressing in a normal direction against the liquid. When this surface changes to concave, this force becomes less, in proportion to the curvature. When the surface becomes convex, this force increases in the same proportion.

If now a capillary tube be dipped into water or mercury, a concave or a convex meniscus is created respectively; but this meniscus cannot remain on a level with the outside horizontal surface, because in both cases the meniscus pressure is different from the outside surface pressure, exerted in opposite direction; and rise must therefore take place in the case of a concave meniscus, and depression in the case of a convex meniscus in order to equalize the difference in the contending normal forces.

It follows that rise or depression must increase when the curvature of the meniscus increases, that is, when the diameters of the tubes decrease.

Laplace arrives at these results by strictly mathematical reasonings and tests the correctness of his theory by applying it to different capillary phenomena.

72. 1807. LINK, H. F. Fortgesetzte Untersuchung ueber Adhaesion tropfbarer Koerper. Gilb. Ann., Vol. 26, p. 147-151.

Making experiments on the displacement of liquids from solid plates by other liquids, in order to decide between the theory of surface attraction by Carradori and the existence of repellent vapors as presumed by Prevost. (See Nos. 53 and 40.) 73. 1807. TRALLES. Correction by Senkwagen (areometers.) Gilb. Ann., Vol. 27, p. 255.

In determining specific gravities by means of areometers, the liquid when wetting the stem, rises around it, producing a force which exerts a pull downward, thus requiring a correction which may be determined by experiment. 74. 1808. CLAIRAUT. Théorie de la figure de la terre.

p. 105-128.

Paris, 1808,

Clairaut was the first to subject the phenomenon of capillary action to an exact mathematical analysis, (see No. 64.) but his solution of the problem fails to account for the experimental law observed by Jurin. (See No. 16.)

75. 1808. LINK. Ueber Anziehung und Verwandtschaft. Gilb. Ann.,

Vol. 30, p. 12-22.

Reiterates his theory of the nature of the solid state, (the smallest particles of a solid are supposed to be liquid surfaces, in the shape of lamels or fibers,) (see No. 70.) Solution takes place by the liquid entering the interstices between the lamels, then by virtue of mutual attraction, the surfaces vanish. and the solid becomes fluid. Speed of solution is not always a measure of affinity, as it also depends on the physical conditions of the solvent and the body to be dissolved.

Chemical affinity is manifested sometimes by merely rubbing substances together, e. g., potassium sulfate and lead acetate liquefy under this condition; reversedly, by an intimate mixture of potassium sulfate and calcium chlorid, double decomposition results, neither product being deliquescent.

76. 1809. BIOT. On the Theory of Laplace, II. Gilb. Ann., Vol. 33, p. 117-140.

Reports on Laplace's Supplement to the theory of capillary action (see No, 64,) which is practically a generalization of his former theory. (See No. 71.)

After establishing the law that in prismatic tubes of like nature, of whatever shape, the bulk of liquid raised above the level by capillarity. is in proportion to the inner circumference of their cross sections, Laplace proceeds to verify his theory by applying it to different capillary phenomena. Observations made by Gay Lussac and Hauy are here recorded.

Finally reviewing preceding theories, Laplace acknowledges the close approach of Jurin's view (see No. 16,) to his own theory as laid down in this supple

ment.

77. 1809.

BRANDES and GILBERT.

Ueber die Theorie von Laplace.

Gilb. Ann., Vol. 33, p. 1-14, 141-182, 275-338, 373-394. Giving a detailed exposition of the theory of Laplace and of its exemplification by various capillary phenomena. (See Nos. 64, 71 and 76.)

78. 1810.

BUSSE. Versuche, um zwischen Cohaesion und Adhaesion zu unterscheiden. Gilb. Ann., Vol. 34, p. 152.

It is presumed that two well polished plates of marble or brass touching each other by their polished surfaces, are held together by two forces which perhaps obey the same law: 1) Cohesion, acting at infinitely small distances, and 2) Adhesion acting at finite spaces. When the plates are moved in a direction parallel to their surface, it is claimed that only the former force is opposing, but when pulled in a normal direction, both forces are to be overcome,

79. 1814. LINK, H. F. Theorie der Fluessigkeit und Festigkeit. Gilb.

Ann., Vol. 47, p. 1-43.

The ultimate essence of fluidity consists in the perfect mutual neutralization of the attraction which the particles in the interior of the fluid exert upon themselves. In viscid liquids there is no complete neutralization, and this causes the particles to move less freely. Such a condition approaches the solid state, which becomes especially manifest at the surface of the liquids. (See No. 70.) Link credits Leidenfrost (See No. 28,) with having previously called attention to the solidity of liquid surfaces. Link then gives his views on solidity and electric action, and on various chemical phenomena.

80. 1816. GIRARD. Mouvement des fluides dans les tubes capillaires. Ann. Chim. Phys., (2) Vol. 1, p. 436.

States that Dubuat (see No. 33a,) experimented on the flow of liquids through capillary tubes, and also reviews the work of Gerstner. (See No. 51.) From his own researches he arrives at a quadratic equation expressing the relation between the velocity of outflow, the constant height of the liquid and the length and diameter of the capillary tube. The quantity of outflow under definite conditions varied in the proportion of 1:4 when the temperature varied from 1° to 86° C. These variations he ascribes to the existence of a liquid film, which lines the inside of the tube, and which increases in thickness when the temperature is increasing. Girard calculates the thickness of this film to be not less than 6-10 mm. at 0 C., but at 100° not more than 1-1000 mm.

81. 1816.

HACHETTE. Mémoire relatif à l'écoulement des fluides par des orifices à minces parois et par des ajutages cylindriques ou coniques. Ann. Chim. Phys., (2) Vol. 3, p. 78.

Records the changes that take place in the velocity and in the shape of a liquid jet, passing through capillary tubes when the following influences are varying: Diameter, length and shape of the outlet tube, the surface against which it rests, the height and the nature of the liquid in the vessel, and the influence of the surrounding air.

82. 1817. FARADAY. On the escape of gases through capillary tubes. Quart. Jour. Science, Vol. III, p. 354.

Desiring to ascertain whether there was any connection between the mobility of gases and their specific gravities, Faraday observed the time which was necessary for different gases to escape through a capillary tube of 20 inches in length, attached to a copper vessel holding 100 cubic inches, during which time the pressure was reduced from 4 atmospheres to 14. The result seemed to demonstrate that the relative mobilities of the gases are in inverse ratio to their specific gravities. At low pressures, however, there was no apparent connection between the densities of gases and their passage through narrow tubes. 83. 1817. PETIT. Observations sur les tubes capillaires.

Phys., (2) Vol. 4, p. 54.

Ann. Chim.

Defends the theory of Laplace against some doubts which were raised by Brunacci in Giornale di Fisica, Chimica, etc.

84. 1817. GIRARD. Ecoulement linéaire de diverses substances liquides par des tubes capillaires de verre. Ann. Chim. Phys., (2) Vol. 4, p. 146.

The velocity of motion of a fluid through a capillary tube depends on two distinct influences:

The specific viscosity of the fluids.

The attraction of the material of the outlet tube for the fluid.

The latter influence causes the formation of a liquid film lining the interior of the outlet tube. (See No. 80.) At temperatures below the boiling point, this influence will prevail over the first one. It is shown, for example, that oil of turpentine, and even a syrupy solution of sugar in water require less time to fill a given volume than does alcohol flowing through the same tube at the same temperatures. However, near the boiling point of the fluids, the second influence will vanish, and the viscosity is then probably measurable by the length of time which is necessary to fill a given volume. The fact that mercury flows out equally fast at different temperatures, supports the film theory.

85. 1817. HACHETTE. Sur les veines fluides qui se forment dans les ajutages cylindriques et coniques. Ann. Chim. Phys., (2) Vol. 5, p. 52.

Studied the conditions under which a fluid running through a tube, will All out this tube, or contract within it thus partly separating from the tube.

86. 1817. PETIT. Lettre relative à la critique de la théorie capillaire. Ann. Chim. Phys., (2) Vol. 5, p. 404.

Concerning the controversy with Brunacci, (see No. 83.)

86a. 1817.

EMMETT. On capillary action. Phil. Mag., (2) Vol. 1, p. 115-332. (1817.)

Studied the influence of temperature on capillary phenomena. (See C. Wolf, Pogg. Ann., Vol. 101, p. 550. (1857.)

87. 1817. GIRARD. Sur l'écoulement de l' Ether et de quelques autres fluides par des tubes capillaires de verre. Ann. Chim.

Phys., (2) Vol. 6, p. 225-34.

Starting from the proposition that the viscosities of liquids, when they are near their boiling point, are then measurable by the time required for a given amount to flow through capillary tubes, (see No. 84.) Girard finds that the viscosities of ether, water and alcohol at their boiling points, are in the proportion of 80: 107: 300. Thus alcohol proves to be more viscid than water.

Girard further demonstrates that the viscosity of ether and water maintain their proportionality also at lower temperatures, while the viscosity of alcohol increases in a much greater ratio when the temperature decreases.

Finally Girard observed the ascent of ether, alcohol, milk and water in capillary tubes, finding, as he expected, their succession different from their classification according to their specific viscosities.

88. 1819. LAPLACE. Considérations sur la théorie des phénomènes capillaires. Ann. Chim. Phys., (2) Vol. 12, p. 5.

General reflections suggested by his theory on capillarity, (see No. 64,) also demonstrates that Thos. Young's idea of the existence of both an attractive and a repellent (caloric) power between the smallest particles (see No. 63,) is in accord with his own theory.

89. 1819. GIRARD. Mémoire sur les atmosphères liquides, et leur influence sur l'action mutuelle des molécules solides qu'elles enveloppent. Mém. Ac. R. Sc. Inst. France, Vol. IV, p. 1-98. Deduces certain laws from the phenomenon of particles settling within a liquid, advocating the existence of a líquid film surrounding each particle. 90. 1821. YOUNG, THOMAS, Dr. (?) (A letter signed S. B. L.) Remarks on the depression of mercury in glass tubes. Quart. Jour. Science, Vol. XI, (1821) p. 83-85.

While rejecting a sweeping statement made by Mr. Ivory in the Encyclopædia Britannica, which abruptly denied to Thos. Young, all his merits with regard to the theory of capillarity, the latter or his representative points out that in the Encycl. Brit. Suppl., (1819) Art. Fluids, edited by Mr. Ivory, there occurred a series of numerical errors in the figures for the depression of mercury in glass tubes. 91. 1821. LAPLACE. Sur l'attraction des corps sphériques, et sur la répulsion des fluides élastiques. Ann. Chim. Phys., (2) Vol. 18, p. 181.

Discusses the attraction one sphere exerts upon another which it surrounds, and gives a theory of the gaseous state, assuming each molecule to be surrounded by a heat atmosphere which counteracts the attraction between each two molecules. From the algebraic formula, which expresses his theory, the laws of Mariotte (Boyle) and of Gay Lussac are readily deducible.

92. 1821. LAPLACE. Eclaircissements de la théorie des fluides élastiques. Ann. Chim. Phys., (2) Vol. 18, p. 273.

A paper, largely embracing theoretical considerations.

93. 1821. NAVIER. Sur les lois du mouvement des fluides, en ayant égard à l'adhésion des molécules. Ann. Chim. Phys., (2) Vol. 19, p. 245.

Navier establishes an elaborate mathematical expression for the velocity of motion of liquids through square tubes, and verifies his result by applying to it the observations made by Girard. (See No. 80.)