On the Diffusion of Metals. 



281 



Frederick the Great. Politische Correspondenz. Bd. XKII. 4 to. 



Berlin 1895. K. Preussische Akademie, Berlin. 



Mcintosh (W. C), F.R.S. The St. Andrews Marine Laboratory 



nnder the Fishery Board for Scotland. 8vo. Paris 1895. 



The Author. 



Pliicker (J.). Gesaminelte Wissenschaftliche Abhandlungen. Bd. 



II. 8vo. Leipzig 1896. 



K. Gesellschaft der Wissenschaften, Gottingen. 

 Rainbaut (A. A.). On the Position of Encke's Comet as deduced 



from Photographs taken by Mr. W. E. Wilson. 8vo. Dublin 



1895. The Author. 



Startin (J.). A Pharmacopoeia for Diseases of the Skin. 12mo. 



Bristol 1896. The Author. 



February 20, 1896. 

 Sir JOSEPH LISTER, Bart., President, in the Chair. 



A List of the Presents received was laid on the table, and thanks 

 ordered for them. 



The Bakerian Lecture was delivered as follows : — 



Bakerian Lecture. — " On the Diffusion of Metals." By W. C. 

 Roberts-Austen, C.B., F.R.S., Professor of Metallurgy, 

 Royal College of Science. Received February 20, 1896. 



(Abstract.) 

 Paet I. — Diffusion of Molten Metals. 



In the first part of the paper the author alludes to some earlier 

 experiments he made in 1883 on the diffusion of gold, silver, and 

 platinum in molten lead. He points out that although the action of 

 osmotic pressure in lowering the freezing point of metals has been 

 carefully examined, very little attention has been devoted to the 

 measurement, or even to the consideration, of the molecular move- 

 ments which enable two or more metals to form a truly homogeneous 

 fluid mass. The absence of direct experiments on the diffusion of 

 molten metals is probably explained by the want of a sufficiently 

 accurate method. Ostwald had stated, moreover, with reference to 

 the diffusion of salts, that " to make accurate experiments in diffu- 

 sion is one of the most difficult problems in practical physics," and 



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