VI 



February 27, 1890. 



Pape 



Croonian Lecture. — The Relations between Host and Parasite in 

 certain Epidemic Diseases of Plants. By H. Marshall Ward, 

 M.A., F.R.S., late Fellow of Christ's College, Cambridge, Professor of 

 Botany in the Forestry School, Royal Indian Engineering College, 

 Cooper's Hill 213 



List of Presents 216 



On the Steam Calorimeter. By J. Joly, M.A., B.E., Assistant to the 

 Professor of Civil Engineering, Trinity College, Dublin (Plates 6, 7).... 218 



A Milk Dentition in Orycteropus. By Oldfield Thomas, Natural History 

 Museum (Plate 8) 246 



On the Effect of the Spectrum on the Haloid Salts of Silver. Bv 

 Captain W. de W. Abney, C.B., RE., D.C.L., F.E.S., and G. S. 

 Edwards, C.E 249 



No. 289,— March 6, 1890. 



List of Candidates 276 



On a second Case of the Occurrence of Silver in Volcanic Dust, namely, 

 in that thrown out in the Eruption of Tunguragua in the Andes of 

 Ecuador, January 11th, 1886. By J. W. Mallet, F.R.S., V.P.C.S., 

 University of Virginia 277 



On the Tension of Recently Formed Liquid Surfaces. By Lord Rayleigh, 

 Sec. R.S 281 



On the Development of the Ciliary or Motor Oculi Ganglion. By J. C. 

 Ewart, M.D 287 



The Cranial Nerves of the Torpedo. (Preliminary Note.) By J. C. 

 Ewart, M.D '. 290 



List of Presents , 292 



March 13, 1890. 



On the Organisation of the Fossil Plants of the Coal-measures. Part 

 XVII. By Wiiliam Crawford Williamson, LL.D., F.R.S., Professor 

 of Botany in the Owens College, Manchester 294 



The Nitrifying Process and its Specific Ferment. By Percy F. Frank- 

 land, Ph.D., B.Sc. (Lond.), A.R.S.M., &c, Professor of Chemistry in 

 University College, Dundee, and Grace C. Frankland 296 



List of Presents 298 



March 20, 1890. 



Bakerian Lecture. — The Discharge of Electricity through Gases. (Pre- 

 liminary Communication.) By Arthur Schuster, F.R.S., Professor of 

 Physics in Owens College, Manchester 300 



List of Presents 300 



