CONTENTS of N° 240.— Fourth Series. 



I. On the Dynamical Theory of Heat. By Joseph Gill, Esq. page 1 



II. On Vortex-rings in Air. By Professor Robert Ball 12 



III. On C. S. Lyman's new form of Wave-apparatus 14 



IV. On the Velocity of Sound in Tubes. By A. Kundt 22 



V. On the Theory of Pressure in Fluids. By R. Moon, M.A., 

 Honorary Fellow of Queen's College, Cambridge . 27 



VI. Description of a new Thermostat. By Frederick Guthrie, 

 Ph.D., F.R.S.E., Professor of Physics and Chemistry, Royal College, 

 Mauritius . . 30 



VII. On the Expansion of Solids by Heat. By M. H. Fizeau . . 31 



VIII. On the comparative Efficiency of different Forms of the Spec- 

 troscope. By Edward C. Pickering 39 



IX. An Optical Experiment. By John C. Douglas, East-India 

 Government Telegraph Department 43 



X. On Purification of Sewage. By G. W. Wigner, F.R.A.S. 46 



XI. Notices respecting New Books :— A Dictionary of Chemistry and 

 the Allied Sciences. By Henry Watts, B.A., F.R.S. — Celestial Ob- 

 jects for Common Telescopes. By the Rev. T. W. Webb, M.A., 

 F.R.A.S 47-52 



XII. Proceedings of Learned Societies : — 



Royal Society : — Dr. Macquorn Rankine on Waves in Liquids ; 

 Mr. William Huggins on the Spectra of the Sun, and of 

 some of the Stars and Nebulae, with an attempt to determine 

 therefrom whether these Bodies are moving towards or from the 

 Earth, and on the Spectrum of Brorsen's Comet, 1868; Mr. 

 Thomas Graham on the Occlusion of Hydrogen Gas by Metals. 52-68 



Royal Institution : — Dr. William Odling on some Effects of 

 the Heat of the Oxyhydrogen Flame 68 



Geological Society: — Mr. H. Woodward on Palaeozoic Crus- 

 tacea from the Upper Silurian rocks of Lanarkshire ; Prof. R. 

 Harkness and Dr. H. A. Nicholson on the Coniston Group ; 

 Dr. A. Leith Adams on the Death of Fishes on the coast of 

 the Bay of Fundy ; Mr. R. Atkins on Volcanoes in the New 

 Hebrides and Banks Islands ; Mr.W. H. Flower on Thylacoleo 

 carnifecc ; Mr. E. Hull on the Carboniferous district of Lanca- 

 shire and Yorkshire 71-74 



XIII. Intelligence and Miscellaneous Articles: — 



On the Spectrum of Brorsen's Comet, by Father Secchi 75 



On Gilding Glass for the Preparation of Optical Mirrors, by W. 



Wernicke 77 



On some special Electromagnetic Phenomena, and on Weber's 



Hypothesis, oj^Electromagnetism, by E. Villari 79 



Application of the Vibrations of Compound Bars to determining 



the Velocity of Sound, by J. Stefan 80 



%* It is requested that all Communications for this Work may be addressed, 

 post-paid, to the Care of Messrs. Taylor and Francis, Printing Office, Red 

 Lion Court, Fleet Street, London. 



