CONTENTS of N° 80S.— Fourth Series. 



I. On the Eelations between the characteristic Quantities occurring 



in Central Motions. By E. Clattsitjs page 1 



II. On the Composition and Origin of the Waters of a Salt Spring 

 in Huel Seton Mine, with a Chemical and Microscopical Examina- 

 tion of certain Eocks in its vicinity. By J. Aethue Phillips, 

 M.Inst.CE., F.G.S., F.C.S., Ac. (With a Plate.) 26 



III. On Negative and Fractional TInitates. By W. H. "Walenn. . 36 



IV. On some Eesults of the Earth's Contraction from Cooling, in- 

 cluding a discussion of the Origin of Mountains. By James D. Dana. 41 



V. On Thermodiffusion of Grases. By "W. Feddeesen, of Leipzig. 55 



VI. Determination of Degrees of Heat in Absolute Measure. By 



L. Loeenz, of Copenhagen 62 



VII. Notices respecting New Books : — Light Science for Leisure 

 Hours. Second Series. By Eichaed A. Peoctoe, B.A. — Selections 

 from the Portfolios of the Editor of the Lunar Map and Catalogue. 77-79 



VIII. Proceedings of Learned Societies : — 



Eotal Society : — Dr. J. Jago on Visible Direction : being an 

 Elementary Contribution to the Study of Monocular and Bin- 

 ocular Vision 80 



IX. Intelligence and Miscellaneous Articles : — 



On Induced Currents and Derived Circuits, by John Trow- 

 bridge .. 84 



On Electrical Figures on Conductors, by H. Schneebeli 86 



Note on G-aseous Pressure, by Bobert Moon, M.A., Honorary 

 Fellow of Queen's College, Cambridge 87 



Note on the use of a Diffraction-" grating " as a substitute for 

 the Train of Prisms in a Solar Spectroscope, by Prof. C. A. 

 Toung 87 



On Duplex Telegraphy, by H. Highton 88 



*** 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. 



