INDEX. 



563 



Potassium, on the atomic weight of, 

 207. 



Potential energy, on the phrase, 88. 



Pratt (Archdeacon) on the figure of 

 the earth, 10, 145, 261, 332, 445. 



Preece (W. H.) on the British- Asso- 

 ciation unit for electrical measure- 

 ments, 397. 



Preyer (M.) on a new method of de- 

 termining the amount of colouring- 

 matter in the blood, 446. 



Protagon, researches on, 448. 



Radiation and vapour, observations 

 on, 283. 



Rankine (W. J. M.) on the phrase 

 potential energy, and on the defi- 

 nitions of physical quantities, 88. 



Ransome (Dr. A.) on some of the 

 conditions of molecular action, 360. 



Roberts (S.) on the order of the con- 

 ditions that an algebraical equation 

 may have a set of multiple roots, 

 530. 



Robinson (Rev. T. R.) on the means 

 of increasing the quantity of elec- 

 tricity in induction-machines, 63. 



Rodwell (G. F.) on some effects pro- 

 duced by a fluid in motion, 99. 



Rood (Prof. O. N.) on a theory pro- 

 posed by Fresnel, and on a mode of 

 measuring the size of very fine par- 

 ticles, 540. 



Royal Society, proceedings of the, 63, 

 224, 304, 391, 543. 



Rudorff (M.) on solid phosphuretted 

 hydrogen, 61. 



Saline solutions, on the relations ex- 

 isting between the composition, 

 density, and refracting-power of, 

 555. 



Scheibler (M.) on the constitution of 

 mellitic acid, 449. 



Schiitzenberger (P.) on the substitu- 

 tion of the metal in a salt by elec- 

 tro-negative elements, 140. 



Schwendler (L.) on the galvanometer 

 resistance to be employed in test- 

 ing with Wheatstone's diagram, 29. 



Sea, on the influence of a change in 

 the obliquity of the ecliptic on the 

 level of the, 426. 



Siemens (C. W.) on the conversion of 

 dynamical into eleetrical force, 469. 



Silicon, on some compounds of, 451. 



Silver, on the atomic weight of, 192. 



Sodium, on the atomic weight of, 207. 



Soils, on the thermal capacity of va- 

 rious kinds of, 56. 



Solar spots, on the distribution of, 

 79. 



Sonorous vibrations, on the action of, 

 on gaseous and liquid jets, 375. 



Sound, on an apparatus for the direct 

 measurement of the velocity of, in 

 the atmosphere, 36. 



Spectra of the meteors of November 

 1866, on the, 234. 



Spectrum, solar, observations on cer- 

 tain lines of the, 76, 78. 



Stahlschmidt (M.) on the reducing- 

 action of zinc, 62. 



Star-colours, on the estimation of, 

 557. 



Stas (M.) on the determination of 

 atomic weights, 187. 



Steam, on the expansion of super- 

 heated, 236. 



Stewart (B.) on the distribution of 

 solar spotted areas in heliographic 

 latitude, 79; on the heating of a disk 

 by rapid rotation in vacuo, 224. 



Stone (E.. J.) on the dynamic theory 

 of deep-sea tides, 318. 



Stroboscopic disks, on the applica- 

 tion of the principle of, to the opti- 

 cal analysis of vibrating bodies, 16. 



Sylvester (Prof.) on the multiplica- 

 tion of partial differential operators, 

 48. 



Tait (P. G.) on the heating of a disk 

 by, rapid rotation in vacuo, 224. 



Telescopes, aplanatic, on, 161. 



Thermometers, on the diminution of 

 difference between exposed and 

 shaded, in upper regions of the at- 

 mosphere, 213. 



Tidal friction, on the theory of, 400. 



Tides, on the dynamical theory of 

 deep-sea, 165, 318, 400. 



Topler (Dr. A.) on the application of 

 the principle of stroboscopic disks 

 to the optical analysis of vibrating 

 bodies, 16; on a method of deter- 

 mining differences of density in 

 transparent media, 75. 



Tomlinson (C.) on some phenomena 

 connected with the adhesion of 

 liquids to liquids, 401. 



Tyndall (Prof. J.) on sounding and 

 sensitive flames, 92 ; on the action 

 of sonorous vibrations on gaseous 

 and liquid jets, 375 ; on the action 



