38 SECTIONAL ADDRESSES. 
water. On September 17 he showed that cells containing muriatic acid 
and sulphuric had given the same volume of hydrogen when connected in 
series, and he was now busy constructing a simple apparatus to measure 
the quantity of electricity by means of the volume of gas produced by it. 
‘The instrument offers the only actual measurer of voltaic electricity 
which we at present possess. ... Ihave therefore named it a voLTa- 
ELECTROMETER.” Today, following Faraday, we define our practical 
unit of current by its electrolytic action, and we use his name to denote 
the fundamental unit of electrochemistry. 
On September 19, among his observations, he notes, ‘ Will not white 
hot diamond conduct. If so may perhaps crystallise carbon at white 
heat by power of the voltaic battery.’ 
He had been worried by the contraction, on standing, of the mixture 
of oxygen and hydrogen obtained in the electrolysis of sulphuric acid. 
He traced this to the catalytic activity of the platinum electrode, and 
showed that the positive and not the negative was effective. This 
observation led him to spend some weeks investigating the conditions 
under which platinum and other metals would assist the combination of 
various gases, when he discovered the retarding effects caused by small 
quantities of gases such as olefiant gas, carbonic oxide and sulphuretted 
hydrogen. The results were communicated to the Royal Society on 
November 30. 
Faraday then returned to the investigation of the amount of chemical 
action produced by the current, and as he recognised that in the electrolysis 
of aqueous solutions it was doubtful whether the elements liberated at the 
poles were to be regarded as primary or secondary products, he extended 
the inquiry to include fused substances, which would be free from this 
ambiguity. On December 17 he wrote in his note-book, ‘ Proceeded to 
decompose dry chlorides, oxides, etc. to ascertain if there also the 
decomposition was definite and what the equivalent numbers would be.’ 
So quickly was the final stage in the investigation accomplished that on 
January 9, 1834, the paper containing the Laws of Electrolysis was 
communicated to the Royal Society. In the first experiment on 
December 17 fused stannous chloride in a glass tube was decomposed with 
platinum wire poles with a voltameter in series, and the weight of the 
tin liberated compared with the weight of water (0-26486 grain) 
decomposed in the voltameter. ‘1-76 of tin had been electro-chemically 
evolved at the exode and of course a corresponding portion of chlorine 
at the cisode. 
Ww T 
Now 0:26486 : 1:76 : : 9 : 59-805 the tin. 
The number for Tin is given 58, which is very near indeed for a first 
experiment, and shows that the electro-chemical equivalent is the same 
as the Chemical equivalent here.’ Note Faraday’s first efforts at a new 
terminology, exode and cisode. Later on the same day the word ‘ pole,’ 
which suggests the idea of attraction or repulsion, was struck out and 
‘ electrode ’ written above it for the first time. 
~ 
2 The name was contracted to voltameter five years later. 
