vi 



Page 



Researches on Chemical Equivalence. Part II. Hydric Chloride and 

 Sulphate, By Edmund J. Mills, D.Sc., F.R.S., and James Hogarth .... 270 



Researches on Lactin. By Edmund J. Mills, D.Sc, F.R.S., "Young" 

 Professor of Technical Chemistry in Andersons College, Glasgow, and 

 James Hogarth 273 



On the Microrheometer. By J. B. Hannay, F.R.S.E., E.C.S., lately 

 Assistant Lecturer on Chemistry in Owens College, Manchester 279 



Limestone as an Index of Geological Time. By T. Mellard Reade, C.E., 

 F.G.S., F.R.I.B.A 281 



Preliminary Note on the Substances which produce the Chromospheric 

 Lines. By J. Norman Lockyer, F.R.S 283 



January 30, 1879. 



On the Effect of Heat on the Di-iodide of Mercury, Hgl<j. By G. F. 

 Rodwell, Science Master, and H. M. Elder, a Pupil, in Marlborough 

 CoUege 284 



A Comparison of the "Variations of the Diurnal Range of Magnetic 

 Declination as recorded at the Observatories of Kew and Trevandrum. 

 By Balfour Stewart, F.R.S. , Professor of Natural Philosophy in Owens 

 College, Manchester, and Morisabro Hiraoka , 288 



On the Determination of the Rate of Vibration of Tuning Forks. By 

 Herbert McLeod, F.C.S., and George Sydenham Clarke, Lieut. R.E 291 



On certain Means of Measuring and Regulating Electric Currents. By 

 C. William Siemens, D.C.L., F.R.S. (Plates 4, 5) 292 



List of Presents 297 



No. 193.— February 6, 1879. 



On certain Dimensional Properties of Matter in the Gaseous State. 

 Part I. Experimental Researches on Thermal Transpiration of Gases 

 through Porous Plates, and on the Laws of Transpiration and Im- 

 pulsion, including an Experimental Proof that Gas is not a Continuous 

 Plenum. Part II. On an Extension of the Dynamical Theory of Gas 

 which includes the Stresses, Tangential and Normal, caused by a Vary- 

 ing Condition of the Gas, and affords an explanation of the Phenomena 

 of Transpiration and Impulsion. By Osborne Reynolds, F.R.S., Pro- 

 fessor of Engineering at Owens College, Manchester 304 



Absorption of Gases by Charcoal. Part II. On a new Series of Equiva- 

 lents or Molecules. By R. Angus Smith, Ph.D., F.R.S 322 



February 13, 1879. 



Note on the Development of the Olfactory Nerve and Olfactory Organ of 

 Vertebrates. By A. Milnes Marshall, M.A., D.Sc, Fellow of St. John's 

 College, Cambridge t 324 



