588 SCIENTIFIC RECORD FOR 1885. 



those giveD by capillary tubes are due in the main to two erroneous as- 

 sumptions, which may cause an error of even 10 per cent. He gives a 

 table of the corrected values for ten liquids. {Phil. Mag., Jnly, 1885, 

 V, XX, 51.) In a paper on the theory of pendent drops the same author 

 shows that the value of the surface tension of a liquid may be deduced 

 from the measurement of the value of the inclination of the tangent of 

 the curved surface of a pendent drop to the axis, measured at a single 

 level, that level being so chosen that the tangent is there vertical. 

 {Phil. Mag., January, 1885, V, xix, 46; J. Phys., October, 1885, II, iv, 

 466.) 



Worthington has devised a capillary multiplier, which consists simply 

 of a rectangular strip of platinum foil of known length rolled into a 

 cylindrical coil, the successive convolutions being kept separate at a dis- 

 tance of about 2°^™ by means of a strip of glass beads in the upper por- 

 tion of the coil. The lower edges of the convolutions are in the same 

 plane, and, as when in use, the coil hangs from one end of a balance 

 beam, this plane is horizontal. By immersing the lower edge in any 

 liquid and measuring by weights in the opposite scale-pan the pull on 

 the coil the surface tension may be calculated. {Phil. Mag., January, 

 1885, V, XIX, 43; J. Phys., October, 1885, II, iv, 467.) 



Eother has measured the capillary constant of several saline solutions, 

 and also of various mixtures of these solutions. ( Wied. Ann., xxi, 576; 

 J. Phys., November, 1885, II, iv, 520.) The paper of Reinold and Riicker 

 on the influence of an electric current in modifying the rate of thinning 

 of a liquid film has appeared in full. {Phil. Mag., February, 1885, V, 

 XIX, 94.) Riicker has delivered a lecture on liquid films before the 

 Royal Institution, giving a resume of the investigations on this subject 

 made by himself in conjunction with Reinold. {Nature, July, 1885, 

 xxxti, 210.) 



Warburg and Sachs have studied the influence of increasing density 

 on the viscosity of liquids, and have calculated the coefficient of friction 

 from the compressibility. This coefficient increases for carbon dioxide, 

 ether, and benzene, and diminishes for water. This latter fact was es- 

 tablished by Rontgen in 1881. ( Wied. Ann., xxii, 510, 518 ; J. Phys., 

 November, 1885, II, iv, 519.) 



Newall has investigated the phenomena of colliding water-jets and 

 has obtained some curious results. If two horizontal jets of water, 

 issuing from similar glass nozzles and fed from two glass bottles, be 

 made to collide at a small angle the jets, if tolerably clean and dust- 

 free water be used, rebound from one another, but may be made to 

 unite by connecting the terminals of a battery with the water in the 

 two bottles. The surface of separation between the colliding jets is ver- 

 tical and shows the colors of thin plates with remarkable brilliancy, due 

 undoubtedly to a thin film of air, as Rayleigh has shown the two to be 

 electrically insulated from one another. The author investigated the 

 effect of a gradual increase of electromotive force upon these colors, 



