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CONTENTS. 



(A) 

 VOL. 213. 



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I. On the Refraction and Dispersion of the Halogens, Halogen Acids, Ozone, Steam, 



Oxides of Nitrogen and Ammonia. By CLIVE CUTHBEKTSON, Fellow of 

 University College, London University, and MAUDE CUTHBERTSON. Commu- 

 nicated by A. W. POSTER, F.R.S. page 1 



II. On a Cassegrain Rejlector with Corrected Field. By Dr. R. A. SAMPSON, 



F.R.S. 27 



III. The Thermal Properties of Carbonic Acid at Low Temperatures. By C. FBEWEN 



JENKIN, M.A., M.Inst.C.E., frofessor of Engineering Science, Oxford; and 

 D. R. PYE, M.A., Fellow of New College, Oxford. Communicated by Sir 

 J. ALFRED EWING, K.C.B., F.R.S. 67 



IV. The Capacity for Heat of Metals at Different Temperatures, being an Account 



of Experiments performed in the Research Laboratory of the University 

 College of South Wales and Monmouthshire. By E. H. GRIFFITHS, Sc.D., 

 F.R.S., and EZER GRIFFITHS, B.Sc., Fellow of the University of Wales . 119 



V. On the General Theory of Elastic Stability. By R. V. SOUTHWELL, B.A., Fellow 



of Trinity College, Cambridge. Communicated by Prof. A. E. H. LOVE, 



F.R.S. 187 



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