CONTENTS OF VOL. XLVL 



(FOURTH SERIES.) 



NUMBER CCCIIL— JULY 1873. 



Page 

 Prof. R. Clausius on the Relations between the characteristic 



Quantities occurring in Central Motions 1 



Mr. J. A. Phillips on the Composition and Origin of the 

 Waters of a Salt Spring in Huel Seton Mine, with a Che- 

 mical and Microscopical Examination of certain Rocks in 



its vicinity. (With a Plate.) 26 



Mr. W. H. Walenn on Negative and Fractional Unitates . . 36 

 Prof. J. D. Dana on some Results of the Earth's Contraction 

 from Cooling, including a discussion of the Origin of Moun- 

 tains 41 



M. W. Feddersen on Thermodiffusion of Oases 55 



M. L. Lorenz on the Determination of Degrees of Heat in 



Absolute Measure 62 



Notices respecting New Books : — 



Mr. R. A. Proctor's Light Science for Leisure Hours. 



Second Series 77 



Selections from the Portfolios of the Editor of the Lunar 



Map and Catalogue 79 



Proceedings of the Hoyal Society : — 



Dr. J. Jago on Visible Direction : being an Elementary 

 Contribution to the Study of Monocular and Binocular 



Vision 80 



On Induced Currents and Derived Circuits, by John Trow- 

 bridge 84 



On Electrical Figures on Conductors, by H. Schneebeli .... 86 

 Note on Oaseous Pressure, by Robert 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. Young 87 



On Duplex Telegraphy, by H. Highton 88 



NUMBER CCCIV.— AUGUST. 



Dr. H. Morton on the Fluorescent Relations of certain solid 

 Hydrocarbons found in Petroleum Distillates 89 



