On a Realised Sulphurous Acid Steam- Pressure Thermometer, and 
on a Sulphurous Acid Steam-Pressure Differential Thermometer. 
By Sir William Thomson, ...... 532 
On a Differential Thermoscope founded on Change of Viscosity of 
Water with Change of Temperature. By Sir William Thomson, . 537 
On a Thermomagnetic Thermoscope. By Sir William Thomson, . 538 
On a Constant Pressure Gas Thermometer. By Sir W. Thomson, . 539 
Monday, 3 d May 1880. 
On the Occultation of the Star 103 Tauri. (b. a. c. 1572.) By 
Edward Sang, ....... 546 
On Currents produced by Friction between conducting Substances, 
and on a new form of Telephone Receiver. By James Blyth, 
M.A., 548 
Note on the Present Outbreak of Solar Spots. By Professor Piazzi 
Smyth, . . . . . . . 554 
Positive and Negative Electric Discharge between a Point and a Plate 
and between a Ball and a Plate. By Alexander Macfarlane, M.A., 
D.Sc., 555 
Researches in Thermometry. By Edmund J. Mills, D.Sc. Com- 
municated by Professor Crum Brown, . • . . . 562 
Monday , VWi May 1880. 
Preliminary Notice of a Method for the Quantitative Determination 
of Urea in the Blood. By John Haycraft, M.B., B.Sc., . . 564 
On the Phenomena of Variation and Cell-Multiplication in a Species 
of Enteroinorpha. By Patrick Geddes. Communicated by Pro- 
fessor A. Dickson, . . . . . . .571 
On the Accurate Measurements of High Pressures. By Professor Tait, 572 
Sixth Report of the Boulder Committee, Plates XVII., XVIII., XIX., 577 
On Two Masks and a Skull from Islands near New Guinea. By 
Professor Turner, . . . . . .635 
On an Ultra-Neptunian Planet. By Professor G. Forbes, . . 636 
Monday , Itli June 1800. 
Remarks by the Chairman, J. H. Balfour, M.D., on delivering to 
Professor Fleeming J enkin the Keith Prize, . . . 637 
Non-Euclidean Geometry. By Professor Chrystal, . . . 638 
Note on the Theory of the “15 Puzzle.” By Professor Tait, . 664 
On the Constitution of Adult Bone-Matrix and the Functions of 
Osteoblasts. By De Burgh Birch, M.B., Demonstrator of Phy- 
siology in the University of Edinburgh, .... 666 
On Two Unrecorded Eggs of the Great Auk ( A lea impennis ) dis- 
covered in an Edinburgh Collection ; with Remarks on the former 
existence of the Bird in Newfoundland. By Robert Gray, . 668 
On a New Telephone Receiver. By Professor Chrystal, . . 682 
Monday , 21 st June 1880. 
On the Differential Telephone, and on the Application of the Tele- 
phone generally to Electrical Measurement. By Professor 
Chrystal, . . . . . . . .685 
