32 SECTIONAL ADDRESSES. 
the true nature of chlorine. Then came the happy accident in 1813 that 
took him to the Royal Institution at the age of twenty-two to act as 
assistant to Davy, who was then at the height of his powers. Faraday 
was always mindful of the debt he owed to Davy, and doubtless he learned 
much from his skill and experience and from watching his decisive 
experimental methods. We can picture them working alongside one 
another in 1815 during those fourteen crowded days which elapsed between 
the arrival of samples of fire damp from the Northumberland mimes and 
the discovery of the principle of the Davy Lamp—“the result of pure 
experimental deduction—it originated in no accident.’ Faraday soon 
began to carry out investigations himself, and from 1816 a constant stream 
of papers appears under his name. They form no connected series, and 
no general idea underlies them. Some come from suggestions from Davy, 
others arise from casual observations in the laboratory or from some new 
materials to be investigated, and later on there are investigations arising 
out of some practical need, such as those on optical glass and on alloys of 
iron when he attempted to produce rustless steel. The titles of some of 
the papers exhibit Faraday’s wide range of interests and experience :— 
On the Escape of Gases through Capillary Tubes (1817), in which he 
appears as the forerunner of Graham; On the Solution of Silver Com- 
pounds in Ammonia (1818); Combinations of Ammonia with Chlorides 
(1818) ; On two new Compounds of Chlorine and Carbon (1820), in which 
he isolates hexachlorethane and tetrachlorethylene ; On new Compounds 
of Carbon and Hydrogen (1825), in which he isolates benzene and butylene ; 
On the Condensation of Several Gases into Liquids (1823) ; On the Mutual 
Action of Sulphuric Acid and Naphthaline (1826), in which he prepares 
and separates the barium salts of the a and § naphthalenesulphonic 
acids by means of their different solubilities. These investigations show 
Faraday’s capacity as a practical chemist, the neatness and simplicity of 
his experimental methods, the quickness and accuracy of his observation, 
and the completeness with which he treated a subject. It was Faraday’s 
good fortune that so important a substance as benzene was in the gas oil 
given to him by Gordon to investigate, but the remarkable part of the 
work is his separation of benzene by fractional distillation and crystallisa- 
tion, and the accuracy both of his analysis made with the simplest means 
and of his vapour density determinations made by exploding a known 
volume with oxygen and measuring the contraction and the volume of 
carbon dioxide formed. For its date it is a little masterpiece of investiga- 
tion, although a modern examiner might quarrel with results.given to six 
places of decimals. Unlike his later work, these papers are mainly records 
of experiments; they contain few references to theory, and owing to 
Faraday’s scepticism as regards the atomic theory he seems to have taken 
little interest in the problem of the atomic constitution of different sub- 
stances, which was just beginning to perplex chemists. New substances 
were discovered, purified, analysed and described and left almost without 
speculation as to their nature. Naphthalenesulphonic acid is called 
‘ sulpho-naphthalic acid, which sufficiently indicates its source and nature 
without the inconvenience of involving theoretical views.’ 
But in those years Faraday was gaining that first-hand acquaintance 
with the properties of many substances, which was to be invaluable to 
