vi Contents. 



No. I'AGE 



XL. — An Economic Method of . Determining the Average Percentage 

 of Fat in a Cow's Milk. for a Lactation Period. By E. J. 

 -Sheehy, f.r.c.sc.i. (Plates LII-LIII.) (May, 1919.) . 546 

 XLL— The Comparative Variation of the Constituent Substances of 



Cows' Milk. By E. J. Sheehy, f.r.c.sc.i. (May, 1919.) . 574 

 XLII. — Possible Causes of Variation in the Quantity and Quality of - 



.Cows' Milk. By E.-*J. Sheehy, f.r.c.sc.i. (May, 1919.) .585 

 XLIII. — The System n-Butyl Alcohol-Acetone-Water. By Joseph 

 Beilly, m.a., d.sc, f.r.c.sc.i., and Edgar W. Balph. (June, 

 1919.) . . . ... . 697 



XLIV. — The Determination of the Bate of Solution of Atmospheric 

 Nitrogen and Oxygen by Water. Part II. By W. E. 

 Adeney.d.sc, a.r.c.sc.i., f.i.c, and H. G. Becker, a.r.c.sc.i. 

 (September, 1919.) . . . . . .609 



XLV. — An Analysis of the Palaeozoic Eloor of North-East Ireland, 

 with Predictions as to Concealed Coal-fields. By W. B. 

 Wright, b.a., f.g.s. (Plate LIV. — Map.) (September, 

 1919.) . . . . . . .629 



XL VI. — On some Factors affecting the Concentration of Electrolytes in 

 ■ the Leaf-sap of Syringa vulgaris. By T. G. Mason, scb., m.a. 

 (December, 1919.) . . . . . .651 



XLVIL— On Brown's Formula for Distillation. By Sydney Young, d.sc, 



f.r.s. (January, 1920.) . . . . . 66S 



XLVIIL— An Apparatus for the Production of High Static Voltages. By 



J. J. Dowling,' m.a. (January, 1920.) . . . 678 



XLIX. — Award of the Boyle Medal to Professor John A. McClelland, 



m.a., d.sc, f.r.s. , 1917. (August, 1920.) . . . 677 



