320 Mr. A. Tribe. Experimental Researches [Jan. 20, 



In some other respects also, the examination may be said to have 

 borne fruit : for occasion was taken to determine the weights and 

 dimensions of parts, and to show the degree of accuracy which might 

 be looked for in such an instrument, supposing it capable of fulfilling 

 its intended purpose. Some defects of construction also of a general 

 character have been pointed out which may serve as hints to future 

 constructors. 



It should be said in conclusion, that so much of the present paper as 

 deals with Broun's gravimeter in particular, was prepared and sub- 

 mitted as a report in the first instance, to the India Office, and that it 

 was communicated to the Society for publication, by permission of 

 the Secretary of State for India in Council. "What may be called the 

 historical part was subsequently added, by way of introduction, to 

 make it more worthy of that honour. 



II. "Experimental Researches into Electric Distribution as 

 manifested by that of the Radicles of Electrolytes." By 

 Alfred Tribe, F.I.O., Lecturer on Chemistry in Dulwich 

 College. Communicated by Dr. Gladstone, F.R.S. Re- 

 ceived December 15, 1880. 



(Abstract.) 



The paper is divided into three principal parts ; the distribution of 

 the ions of copper sulphate on silver plates ; analogies between the 

 distribution of ions and that of static electricity ; and analysis of 

 electrolytic fields. 



When a solution of copper sulphate is electrolysed with silver 

 electrodes, the negative electrode becomes covered with a deposit of 

 copper, the positive with a coating of silver peroxide. The author 

 has shown that if a metallic rod or plate is placed lengthwise between 

 the electrodes in a liquid undergoing electrolysis, the plate does work 

 identical in kind with that being done by both electrodes. It follows 

 that a silver plate in copper sulphate will be found coated on one part 

 with copper, and on the other with silver peroxide. The superficial 

 distributions of these ions were examined. A rectangular electrolytic 

 cell, a solution of copper sulphate, and copper electrodes were employed. 

 The electrodes were of the same breadth and depth as the cell. In 

 the centre of the liquid, lengthwise and perpendicular to the electrodes, 

 a plate of thin sheet silver was fixed. 



In all cases the distributions of the two ions on the plates or even 

 on bodies of various other shapes, were invariably unsymmetrical, the 

 negative ion generally spreading further than the positive. The dis- . 



