[ 521 ] 



INDEX to VOL. XXI 



ABSORPTION-cell, on a new form 

 of, 80. 



Acids, on the constitution of, 127. 



Ahrens (Mr.), on a new polarizer 

 devised by, 476. 



Air, on the effect of temperature on 

 the viscosity of, 199 ; on the efflux 

 of, as modified by the form of the 

 discharging orifice, 494. 



Atmosphere, on the conservation of 

 energy in the earth's, 453. 



Atmospheric electricity, on the origin 

 and the laws of, 520. 



Ayrton (Prof.) on the seat of the 

 electromotive forces of a voltaic 

 cell, 51 ; on the winding of volt- 

 meters, 100 ; on some thermody- 

 namical relations, 255. 



Baily (W.) on a map of the world 

 on Flamsteed's projection, 415. 



Basalts of Tertiary age, on the, 160. 



Bell (R. G.) on the Pliocene beds of 

 St. Erth, 363. 



Blanford (Dr. W. T.) on the occur- 

 rence of glacial conditions in the 

 Palaeozoic era, 448. 



Bohr (C.) on the deviation of oxygen 

 from Boyle and Mariotte's law, 

 368. 



Books, new : — Ketteler's Theore- 

 tische Optik, 158; Morley's Out- 

 lines of Organic Chemistry, 217 ; 

 Clerke's Popular History of Astro- 

 nomy, 279; Helmholtz's Sensa- 

 tions of Tone, 445 ; Orookes's Se- 

 lect Methods in Chemical Analysis, 

 507 ; Fourth Annual Report of the 

 United States Geological Survey, 

 510; Photo-relief Maps, 511. 



Boys (C. V.) on a machine for sol- 

 ving equations, 241. 



Brodie (Rev. P. B.) on two Rhsetie 

 sections in Warwickshire, 362. 



Brown (J. A.) on Thames Valley 



surface-deposits, 283. 

 Burbury (S. H.) on the foundations 



of the kinetic theory of gases, 481. 

 Calorimetric work, on experimental 



error in, 324. 

 Carbon dioxide, on the effect of tem- 

 perature on the viscosity of, 199. 

 Chambers (Miss J. M.) on a simple 



way of explaining Clerk Maxwell's 



electromagnetic theory of light, 



162. 

 Chree (C.) on bars and wires of 



varying elasticity, 81. 

 Clayden (A. W.) on the determina- 

 tion of the volume of mercury in a 



thermometer, 248. 

 Climates, on geological, 223. 

 Cole (G. A. J.) on spherulitic rocks, 



364. 

 Conductors, on the self-induction 



and resistance of straight, 381. 

 Conic, on the differential equation of 



a, 143. 

 Cornet (F. L.) on phosphatic beds 



near Mons, 513. 

 Croll's (Br.) hypotheses on geological 



climates, on, 223. 

 Cunynghame (H.) on a mechanical 



method of solving quadratic and 



cubic equations, 260. 

 Deprez (M.) on an instrument for 



producing an invariable quantity 



of electricity, 518. 

 Dew, on a new theory of, 483. 

 Diaphragms, on the permeability of 



various, 288. 

 Dixon (W. A.) on the constitution 



of acids, 127. 

 Dolerites of Tertiary age, on the, 160. 

 Dorn (E.) on a proof of the law that 



both electricities are developed at 



the same time and in the same 



