CONTENTS of N° 277.— Fourth Series. 



I. On the Universal Powers of Nature and their Mutual Depend- 

 ence. By L. A. Colding page 



II. Arrangement for the Discharge of long Overland Telegraph 

 Lines. By Louis Schwendler, Esq 20 



III. On the Application of a new Integration of Differential Equa- 

 tions of the Second Order to some unsolved Problems in the Calculus 

 of Variations. By the Rev. Professor Challis, M. A., F.R.S., F.R.A.S. 2 



IV. An Inquiry into the Cause of the Interrupted Spectra of Gases. 

 — Part II. On the Absorption-spectrum of Chlorochromic Anhydride. 

 By G. Johnstone Stoney, M.A., F.R.S., Secretary to the Queen's 

 University in Ireland, and J. Emerson Reynolds, M.R.C.P.E., Keeper 

 of the Mineral Department, and Analyst to the Royal Dublin Society. 41 



V. On the Direct Conversion of Dynamic Force into Electricity. 

 By S. Tolver Preston, Esq 53 



VI. On the Physical Constitution of the Sun. By Professor W. A. 

 Norton 55 



VII. On Increasing the Rigidity of long, thin Metallic Pointers, 

 Magnetic Needles, &c. By John C. Douglas, Science Teacher, G.B., 

 E.I. Gov. Telegraph Department 67 



VIII. Notices respecting New Books :— Mr. J. A. S. Rollwyn's 

 Astronomy Simplified for General Reading, with numerous new Expla- 

 nations and Discoveries in Spectrum Analysis, &c 69 



IX. Proceedings of Learned Societies : — 

 Royal Society : — The Rev. S. J. Perry's Results of Seven 



Years' Observations of the Dip and Horizontal Force at Stony- 

 hurst College Observatory ; Mr; E, J. Stone on an approxi- 

 mately Decennial Variation of the Temperature at the Obser- 

 vatory at the Cape of Good Hope between the years 1841 and 



1870; MM. Wolf and Fritz on Sun-spots ........ 71-7G 



Geological Society « 76 



X. Intelligence and Miscellaneous Articles : — 



On the Microscopic Structure of Hail, by Paul Reinsch 79 



%* 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. 



