IV 
CONTENTS. 
PAGE 
XXIX. Note on a New Species of Lepidodendron from Petty cnr 
( Lepidodenclron Petty cur ense). By R. Kidston, F.R.S. 
L. & E., F.G.S., Foreign Mem. Kaiserl. Mineral. Gesell. 
zu St Petersburg, ..... 
(Issued separately September 9, 1907.) 
XXIII. On the Application of a Differential Densimeter to the 
Study of some Mediterranean Waters. By John J. 
Manley, M.A., Daubeny Curator, Magdalen College, 
Oxford. ( Communicated by Sir John Murray, K.C.B.) 
With an Appendix, ..... 
( Issued separately September 11, 1907.) 
XXIV. The Electric Conductivity and Refracting Power of Ninety 
Samples of Sea- Water, and a Comparison of these with 
the Salinity and Density. By E. G. Hill, B.A. Oxon, 
D.Sc. Dublin, Professor of Chemistry, Muir College, 
Allahabad. ( Communicated by Sir John Murray, 
K.C.B.), 
(Issued separately September 11, 1907.) 
XXV. The Influence' of Twist on the Strength of a Thread. By 
Thomas Oliver, B.Sc. (Bond, and Edin.), Carnegie Re- 
search Fellow. (Communicated by Dr C. G. Knott), . 
(Issued separately October 2, 1907.) 
XXVI. A New Method of determining the Degree of Twist in 
Single Threads. By Thomas Oliver, B.Sc. (Lond. 
and Edin.), Carnegie Research Fellow. ( Communi- 
cated by Dr C. G. Knott), .... 
(Issued separately October 2, 1907.) 
XXVII. The Composition of Terrigenous Deposits. By F. W. 
Clarke, D.Sc., LL.D., Chief Chemist, U.S. Geological 
Survey. (Communicated by Sir John Murray, K.C.B., 
F.R.S., etc.), . . . . . . 
(Issued separately October 2, 1907.) 
XXVIII. A Preliminary Note on the Optical Rotations (throughout 
the Spectrum), the Electrical Conductivities, and the 
Densities of Mixtures of Sodium-Potassium-Tartarate 
and Ammonium-Molybdate in Aqueous Solution. By 
James Robert Milne, D.Sc., Carnegie Research Fellow 
in Physics, ...... 
(Issued separately October 3, 1907.) 
XXIX. Degenerations following Experimental Lesions in the Motor 
Cortex of the Monkey. By Sutherland Simpson, 
M. D., D.Sc., and W. A. Jolly, M.B. (From the Physio- 
logical Laboratory , University of Edinburgh.) (Com- 
municated by Professor A. E. Schafer, F.R.S.), 
(Issued separately October 3, 1907.) 
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