b Ob^A 



CONTENTS. 



VOL. X. 



PART I. 



PAGE 



I. — An Improved Polarizing Vertical Illuminator. By J. Joly, M.A., 

 D.Sc, F.R.S., Professor of Geology and Mineralogy, Trinity 

 College, Dublin ; Hon. Sec. Royal Dublin Society, ... 1 



II. — How to introduce Order into the Relations between British "Weights 

 and Measures. By G. Johnstone Stoney, M.A., Sc.D., F.R.S. 

 (Plate I.) 



III. — Photographs of Spark-Spectra from the Large Rowland Spectro- 

 meter in the Royal University of Ireland. Part II. : The Ultra- 

 Violet Spark -Spectrum of Ruthenium. By "W. E. Adeney, D.Sc, 

 A.R.C.Sc.L, Curator and Examiner in Chemistry in the Royal 

 University of Ireland, 24 



IV.— The Cohesion Theory of the Ascent of Sap : A Reply. By Henry 

 H. Dixon, Sc.D., Assistant to the Professor of Botany, Trinity 

 College, Dublin, • . 48 



V. — The Petrological Examination of Paving-Sets. Part I. By J. Joly, 

 B.A.I. , Sc.D., F.R.S., F.G.S., Professor of Geology and Minera- 

 logy in the University of Dublin ; Hon. Sec. Royal Dublin Society. 

 (Plates II.-V.), -■..--..■:. . 62 



VI. — On an Irish Specimen Dopplerite. By Richard J. Moss, F.I.C., 



F.C.S., 93 



VII. — Tyloses in the Bracken Fern (Fteris aquilina, Linn.). By T. 

 Johnson, D.Sc, F.L.S., Professor of Botany in the Royal College 

 of Science, and Keeper of tne Botanical Collections, National 

 Museum, Dublin. (Plate VI.), 101 



VIII. — A New Method of producing Tension in Liquids. By J. T. 



Jackson, M.A., 104 



IX. — A Transpiration Model. By Henry H. Dixon, Sc.D., Assistant 



to the Professor of Botany, University of Dublin, . . . .114 



X.— The Levinge Herbarium. By T. Johnson, D.Sc, F.L.S., Pro- 

 fessor of Botany in the Royal College of Science, and Keeper of 

 the Botanical Collections, National Museum, Dublin ; and Miss 

 M. C. Knowles, .......... 122 



