CONTENTS OF VOL. XXIX. 



(FOURTH SERIES.) 



NUMBER CXCIII.— JANUARY 1865. 



Page 

 Mr. D. Forbes's Researches on the Mineralogy of South America I 

 M. C. Martins on the relative Heating, by Solar Radiation, of 

 the Soil and of the Air, on a Mountain and in a Plain .... 10 



Mr. C. J. Monro on a case of Stereoscopic Illusion 15 



Prof. Cay ley on a Quartic Surface 19 



Dr. Rankine on the approximate Graphic Measurement of 

 Elliptic and Trochoidal Arcs, and the Construction of a Cir- 

 cular Arc nearly equal to a given Straight Line. (With a 



Plate.) 22 



Dr. Rankine's Supplement to a Paper on Stream-lines. (With 



a Plate.) , 25 



Dr. Akin on Calcescence 28 



Prof. Tyndall on the History of Negative Fluorescence 44 



Mr. P. G. Tait on the History of Energy 56 



Prof. Magnus on Thermal Radiation 58 



M. de Saint- Venant on the Work or Potential of Torsion. 

 New Method of establishing the Equations which regulate 



' the Torsion of Elastic Prisms . . 61 



Proceedings of the Royal Society : — 



Sir W. Snow Harris's Further Inquiries concerning the 



Laws and Operation of Electrical Force 65 



Proceedings of the Geological Society : — 



Dr. Logan on the occurrence of Organic Remains in the 



Laurentian Rocks of Canada 75 



Dr. J. W. Dawson on the Structure of certain Organic 



Remains found in the Laurentian Rocks of Canada . . 76 

 Mr. T. S. Hunt on the Mineralogy of certain Organic 

 Remains found in the Laurentian Rocks of Canada . . 76 

 Remarks on the Letter published by Dr. J. Davy in the Decem- 

 ber Number of the Philosophical Magazine, by Sir J. F. W. 



Herschel, Bart., F.R.S., &c 77 



On the Discrimination of Compounds of Sesquioxide of Manga- 

 nese and of Permanganic Acid, by Hoppe-Seyler 78 



On the Construction of Double- scale Barometers, by William 

 Mathews, Jun 79 



