483. 1886. BUNSEN, R. Zersetzung des Glases durch Kohlensäure enthalt de capillare Wasserschichten. Wied. Ann., Vol. 29, p. 161-165.

The glass threads used by the author in his absorption experiments (see No. 469) were found to be decomposed by CO2 to the extent of 5.83 %. Part of the CO2 formerly evolved upon warming was, no doubt, due to decomposition of bicarbonate formed, but an additional amount must have been due to other causes.

The author concludes that glass is not a proper material for the study of physical absorption of CO2; the employment of fine threads of platinum or gold is suggested.

484. 1886. ROENTGEN, W. C., and SCHNEIDER, J. Ueber Compressibilität und Oberflächenspannung von Flüssigkeiten. Wied. Ann., Vol. 29, p. 165–213.

The authors prepared aqueous solutions of iodides, bromides, chlorides, nitrates, hydroxides, sulphates and carbonates of hydrogen, ammonium, lithium, potassium and sodium of equimolecular strength. Then they determined the compressibilities and the surface tensions of these solutions. From the elaborate tables thus obtained, the following_conclusion is drawn: Within each group (e. g., HNO 3, H Br, HOH, H2SO4, or Lil, LiNO3, etc.) the liquid with the smaller molecular compressibility has the greater surface tension.

485. 1886. STEFAN, J. Relation between the Theories of Capillarity and Evaporation. Jour. Chem. Soc. Abst., 1887, p. 323, from Wied. Ann., Vol. 29, p. 655-665.

A relation is established between the latent heat of evaporation, the specific gravity of the liquid, and the difference of molecular pressure existing in the interior and the surface of the liquid. For ether, the author finds the enormous interior pressure of 2574 atmospheres, for CS2 he finds 2728 atmospheres. Sir W. Thomson's conclusions as to the connection between evaporation and curvature of evaporating surfaces (see No. 819) are herein confirmed.

486. 1886. DUHEM, P. Application of Thermodynamics to Capillary Phenomena. Phil. Mag., (5) Vol. 22, p. 230–231.

General equations are established on thermodynamical principles, which bring the theory of Thomson (see No. 819) into agreement with those of Laplace and Gauss (see Nos, 64 and 115). The equations are then applied to the two special processes of evaporation and supersaturation.

487. 1886. THOMSON, SIR WILLIAM. Capillary Attraction. A Lecture before the Royal Institution. Nature, Vol. 34,

p. 270-272, 290-294, 366-369.

Starts out by illustrating the immense force of cohesion between two plane water surfaces in immediate contact; capillary elevation is deduced therefrom on the principle of equal work performed. This leads to the demonstration of the principle of surface tension in simple liquids and the tension of the common surface of immiscible and miscible liquids. Finally, some experimental illustrations of capillary phenomena are given, e. g., the capillary behavior of mercury; the form and properties of drops, the displacement of a liquid of strong surface tension (water) by one of less surface tension (alcohol), for which the “tears of strong wine" are an example (see No. 218).

488. 1886. MAGIE, W. F. Note on a Method of Measuring the Surface Tension of Liquids. Amer. Jour. Science, Vol. 131, p. 189-193.

The principle of the method by means of which the author proposed to decide the question of the existence of a contact angle is stated under No. 510. The results herein obtained still leave the question open.

489. 1886.

TRAUBE, J. Ueber die innere Reibungsconstante und die specifische Zähigkeit organischer Flüssigkeiten und ihrer wässrigen Lösungen. Ber. d. Deutsch. Chem. Ges., Vol. 19, p. 871-892.

The apparatus employed by the author to determine the constant of the inner friction of liquids passing through capillary tubes, by Poiseuille-Hagenbach's method (see Nos. 162 and 246), also allows measurements of the weight of falling drops, therefore of capillary constants. The friction constants for a series of alcohols and of organic acids were determined at temperatures between 20° and 60°, and the results illustrated by diagrams in which were included the results of PAGLIANI and BATTELLI (Turin, 1885), for the same liquids at temperatures between 0 and 10° (compare No. 254). The volumes of the drops are proportional to the heights of rise of the liquids in capillary tubes. A further consequence is the rule that the dropping intervals are proportional to the products of friction constants and dropping volumes or capillary rise.

490. 1886. TRAUBE, J. Methode zur Bestimmung des Fuselöls. Ber. d. Deutsch. Chem. Ges., Vol. 19, p. 892-895.

Since aqueous solutions of high-molecular alcohols have a markedly lower capillary rise than corresponding solutions of ethyl alcohol, the presence of fusel oll in diluted spirits may be expected to be recognized by the decrea-e of capillary rise. The apparatus used by the author was previously described (Journal f. prakt. Chem., 1886, p. 177). A table is given, showing the decrease of capillary rise of a 20% spirits containing fusel oil of varying percentages (0 to 1 %) (compare No. 505).

491. 1886. TRAUBE, J. Ueber die Grösse der Maximaltropfen der

gewöhnlichen Alcohole und Fettsäuren, und ihrer wässrigen Lösungen. Ber. d. Deutsch. Chem. Ges., Vol. 19, p. 1673–1679. The law previously stated (see No 489) that the volumes of drops issuing from the lower circular end of a capillary tube are in exact ratio to the capillary heights of rise, does not hold good for very large terminal surfaces of the tube, because the drop size for increasing surfaces attains a maximum. This maximal drop, in other words, is the drop falling from a large horizontal surface. It is a constant, varying only with the cohesion of the fluids. The weight of one drop was determined by counting the drops yielded by a known volume of fluid, and multiplying by the specific gravity. An elaborate table is given, showing the maximal-drop size for alcohols and fatty acids at different temperatures It confirms the natural supposition that the maximal diameter of these drops increases with increasing cohesion.

492. 1886. TRAUBE, J. Ueber die Abhängigkeit der Tropfengrösse von äusseren Einflüssen. Ber. d. Deutsch. Chem. Ges., Vol. 19, p. 1679-1682.

The influence of various conditions upon the size of drops has been exhaustively treated by Guthrie (see No. 276), and is confirmed by the author, especially as to effect of curvature of wall and velocity of flow. Contrary to Guthrie, however, the author is unable to detect an appreciable influence of the material of the wall upon the size and weight of drops; the deviations observed come within the scope of errors of observation. The author finally reiterates a former statement, to the effect that the edge-angle of one and the same liquid against glass and metal is nearly the same, and different from zero.

493. 1886. TRAUBE, J., and BODLÄNDER, G. Ueber die Unter

scheidung von Eiweisskörpern, Leim und Peptonen durch Capillarität. Ber. d. Deutsch. Chem. Ges., Vol. 19, p. 1871-1876. Musculus (see No. 272) classes albumin among the capillary inactive substances. i. e., that do not appreciably reduce the capillary rise of water. This property of albumen of various sources is verified by the authors. Gelatine behaves similarly, but peptones, e. g., those contained in Liebig's extract of beef, are active to a remarkable degree. Their presence in aqueous solutions causes a marked decrease of their capillary rise, respectively decrease of the volume of drops issuing from a vertical capillary tube (see No. 491); in other words, an increase in the number of drops yielded by a given volume of peptonated solutions.

494. 1886. REINOLD, A. W., and RUECKER, A. W. On the Relation between the Thickness and the Surface Tension of Liquid Films. Phil. Trans., 1886, Vol. 177, p. 627-684.

Contrary to the conclusions of previous observers, the surface tension of a soap film remains constant regardless of its thickness, a fact established over a wide range of thicknesses (12 to 1350 micromillimeters). The cause of the sudden discontinuity of the black film (see No. 876) at its edge is still in doubt; its thickness varies only between narrow limits, 7 to 14 micromillimeters, which remains fairly constant soon after its formation. The boundary line of a black film becomes ill defined when an electric current of sufficient intensity is passed through it, but is restored upon cessation of the current.

495. 1886. TRAUBE, J, Capillary Constants and Meniscus Angle. Journ. Chem. Soc. Abst., 1887, p. 101, from Journ. prakt. Chem., [2] Vol. 34, p. 292–311.

Values are obtained for the "specific cohesion" (theoretically the height of capillary rise in tubes of 1 mm. radius, the edge-angle being zero) for fatty alcohols and fatty acids at various degrees of concentration; both propyl and ísopropyl alcohol show a minimum for mixtures of equal weights of the alcohol and water. Another series of determinations with the same fluids was made by measurements of falling drops of these fluids. The volume of the drops was found proportional to the capillary rise in one and the same tube; accordingly, the weight of the drops was found proportional to the product of the height and the specific gravity. The diameter of the tube determines the shape of the drop. 496. 1886. TRAUBE, J. The Weight of Drops, and their Relation to

the Constants of Capillarity and the Capillary Meniscus Angle. Jour. Chem. Soc. Abst., 1887, p. 210-211, from Jour. prakt. Chem., (2) Vol. 34, p. 515–538.

For water and solutions of alcohol of different strengths, the weights of drops and their capillary constants decrease with the increasing curvature of the surface of formation of the drops. This decrease, however, does not begin before a certain degree of curvature, which is different for different liquids, neither is this decrease proportional to the increase in curvature; it appears to be the greater, the smaller the capillary constant of the liquid. He also finds the edge angle of the meniscus of drops of different liquids to be equal or proportional to the meniscus angle of the same liquid in capillary tubes. Further properties of the meniscus of drops are developed.

497. 1887. HELMHOLTZ, H. VON. A Cohesion Experiment. Nature, Vol. 35, p. 456.

If distilled water is placed above a mercury column in a barometric glass tube longer than 760 mm., the cohesion of the water will, provided that no vibrations occur, prevent the mercury column from falling to its barometric height, even if at the lower end a suction is applied down to I mm. vacuum. By means of this contrivance the minimum voltage necessary to electrolyse pure water was ascertained. This minimum occurred at 2.18 volts.

498. 1887.

DUFOUR, PROF.

Nature, June, 1887, p. 209.

Surface Tension and Magnetism.

The influence of a strong magnetic field upon the surface tension of mercury is shown. A jet of mercury issuing from a horizontal capillary tube describes a parabola, the vein being continuous to a certain distance. When allowing a strong electro-magnet to act on the jet, the parabola is stretched, and the continuous part of the vein lengthens.

499. 1887. LENARD, PHILIPP. Ueber die Schwingungen fallender Tropfen. Wied. Ann., Vol. 30, p. 209-243.

The surface tensions (see No. 444) of wa er, soap solution, alcohol and mercury, were deduced from measurements of the weights and the vibrations of falling drops of these liquids, observed by the method of intermittent photography. The surface tension of mercury was found to be 47.10 mg.-mm, for alcohol 2.50, for water from 7.25 to 7.34, these determinations being free from the assumption of an edge angle.

500. 1887. TIMBERG, GUSTAF. Untersuchungen über den Einfluss der Temperatur auf die Capillaritätsconstanten einiger Flüssigkeiten. Wied. Ann., Vol. 30, p. 545–561.

A review of the literature on the influence of temperature upon the constants of capillarity of liquids is given. New experiments are carried out by means of three different methods; viz., the measurement of flat air bubbles in various liquids, the method of adhesion rings and the measurement of the weight of drops (see Nos. 370 and 276). Tables are given, and the results illustrated by curves which nearly all are sloping straight lines. Ether is the liquid whose capillary constants change fastest with temperature; then follow benzol, alcohol, water and salt solutions.

501.

1887. MELDE, F. Ueber einige Anwendungen enger Glas

röhren. Wied. Ann., Vol. 32, p. 659-670.

Describes a simple method for calibrating capillary tubes of 2-mm. inner width and downward. Shows how Boyle's law for gases can be demonstrated by means of a capillary tube closed at one end and containing a measurable volume of air separated from the outer air by a column of mercury. Measurements are taken with the tube first in the upright, and next in the inverted position. The same device can be used to calculate barometric pressure; hence it is called a capillary barometer. Finally, the author shows how capillary tubes can be used to measure the specific gravity of gases by measuring their different velocities (see No. 130).

502. 1887. COLEMAN, J. J. On Liquid Diffusion. Phil. Mag., (5) Vol. 23, p. 1-10.

Graham's experiments (see No. 253) on “jar diffusion" are herein extended over additional salt solutions. The diffusions were conducted in Mohr burettes; the diffusates, in due time, were drawn off fractionally and analyzed. Curves are given which illustrate the heights of diffusion for decreasing percentages. The march of diffusibilities for different salts is analogous to that of atomic and molecular volumes in Mendeleef's arrangement of elements.

503. 1887. SUTHERLAND, W. On the Law of Molecular Force. Phil. Mag., (5) Vol. 21, p. 113–114 and 168-187.

The author generalizes his previously announced molecular law for gases of the inverse 4th power as follows: Any two molecules of matter attract one another with a force proportional directly to the product of their masses, and inversely to the 4th power of the distance between them; the "molic" (astronomic) force acts in the inverse 2nd power. On this basis, the capillary theories of Laplace and Gauss are critically reviewed.

504. 1887. SIEG, E.

Ueber die an Tropfen und Blasen. 37 (1887), p. 167-168.

Bestimmung von Capillaritätsconstanten
Dissert., 1887; also see Nature, Vol.

Quoted in detail by Lohnstein (see No. 552). The author critically reviews Quincke's measurements of capillary constants by the method of flat drops and bubbles, in order to account for the high results obtained by that method. He concludes that in Quincke's measurements the possible error of observation is quite large, and, additionally, the correction formula employed by Quincke is considered insufficient. In measurements of his own with air-free water by Quincke's method simplified, the author finds a lower value for the surface tension, more in accord with that of other observers except Quincke.

505. 1888. ELSWORTHY, H. S. Note on a Modification of Traube's "Capillarimeter." Jour. Chem. Soc. Trans., 1888, p. 102-104. Traube's "capillarimeter," devised to detect the presence of fusel oil in distilled spirits (see Zeitschrift f. Spiritusindustrie, 1886, No. 86), is modified for the purpose of rendering the instrument more sensitive. This is done by fixing the capillary tube in an inclined position. A 20-% spirits (by volume) then rises to a length of 175 mm. against 50 mm. in Traube's instrument. The presence of 1-% fusel oil reduces this height by 25 mm. against 7 mm. in Traube's prototype. A drawback of the method is the probable necessity of reducing the spirit to 20% by volume, which reduces still further an eventual low percentage offusel oil.

506.

1888. RUECKER, A. W. On the Range of Molecular Forces. Jour. Chem. Soc. Trans., 1888, p. 222-262.

A full and interesting history of the researches on this subject, and a summary of results is recorded.

507.

1888.

GOLDSTEIN, M. Rise of Salt Solutions in Capillary Tubes. Jour. Chem. Soc. Abst., 1889, p. 205, from Jour. Russ. Chem. Soc., 1888, Vol. 20, p. 408-415.

An extension of former researches (see No. 458). With concentrated salt solutions of equal percentage, the solution of less molecular weight has the higher capillary rise. Inversely, with solutions of equal capillary height, the solution of less percentage has the higher molecular weight. The difference of capillary heights corresponding to a difference of percentage of salt solution becomes greater for the same difference of percentage of another salt of greater molecular weight.

508.

1888.

GOPPELSROEDER, F. On Capillary Analysis. Phil. Mag., (5) Vol. 25, p. 244.

The basis of this method was laid by the researches of Schönbein; also see the author's former work (see Nos. 259 and 271). Coloring matters in not too concentrated solution may be differentiated by means of filtering paper; the zones, attained after a certain interval of time, are noted, and the zones separately extracted by suitable solvents. Each extract is then examined in a similar manner until zones of the pure coloring matters are obtained. Thus the author found picric acid in sophisticated beer, fuchsine in wine.

509.

1888. BOYS, C. V.

Experiments with Soap Bubbles. Phil. Mag., (5) Vol. 25, p. 409-419.

Two soap bubbles may be pressed together, or even roughly knocked together, without bursting, owing to a film of air between them which they are unable to exclude. Increased pressure, however, destroys the bubbles. The existence of this air film is demonstrated by a series of beautiful lecture experiments on soad bubbles.

510. 1888. MAGIE, W. F. On the Contact Angle between Liquids and Solids. Phil. Mag., (5), Vol. 26, p. 162-183.

In order to decide the much-debated question of the existence of an edgeangle (see Nos. 477 and 480), the author determines a 2, the specific cohesion" for several liquids each by two different methods, both based upon measuring certain dimensions of air bubbles in these liquids under a horizontal glass plate (see No. 312). One of these methods is independent of the assumption of an edge angle; the other takes the edge angle into account; if this angle is really zero, both values ought to be identical. The author finds the angle zero for methyl and ethyl alcohol, formic acid, chloroform aud benzin, the close agreement thus showing the usefulness of the method. The angle is finite for water (though small), for acetic acid (20°), turpentine (17°), petroleum (26°) and ether (16). The author conjectures as to the cause of this contact angle.

511.

1888. VAUTIER, TH. Recherches expérimentales sur la vitesse d'écoulement des liquides par un orifice à mince paroi. Ann. Chim. Phys., (6) Vol. 15, p. 289–375 and p. 433–497. The first of these two elaborate papers proves that Torricelli's law for the velocity of flow of liquids through an orifice at the bottom of the containing vessel holds good also for low pressures and narrow orifices, a case for which the law hitherto had not been tested. The author employs two different methods of measuring the velocity of a jet of water-one an optical, the other a photographic method, both of which are described in minute detail. Furthermore, Poiseuille's law of the inner friction of fluids passing through capillary tubes, is verified (see No. 162). The second paper deals with the application of the photographic method to the study of the flow of viscous liquids through capillary tubes.

512. 1888. QUINCKE, G. Ueber die physikalischen Eigenschaften dünner fester Lamellen. Wied. Ann., Vol. 35, p. 561-580; also see Phil. Mag., Vol. 27 (1889), p. 79–80.