Faraday as a Discoverer | Page 8

to the liquid
condition. In 1844 he returned to the subject, and considerably
expanded its limits. These important investigations established the fact
that gases are but the vapours of liquids possessing a very low
boiling-point, and gave a sure basis to our views of molecular
aggregation. The account of the first investigation was read before the
Royal Society on April 10, 1823, and was published, in Faraday's name,
in the 'Philosophical Transactions.' The second memoir was sent to the
Royal Society on December 19, 1844. I may add that while he was
conducting his first experiments on the liquefaction of gases, thirteen
pieces of glass were on one occasion driven by an explosion into
Faraday's eye.
Some small notices and papers, including the observation that glass
readily changes colour in sunlight, follow here. In 1825 and 1826
Faraday published papers in the 'Philosophical Transactions' on 'new
compounds of carbon and hydrogen,' and on 'sulphonaphthalic acid.' In
the former of these papers he announced the discovery of Benzol,
which, in the hands of modern chemists, has become the foundation of
our splendid aniline dyes. But he swerved incessantly from chemistry
into physics; and in 1826 we find him engaged in investigating the
limits of vaporization, and showing, by exceedingly strong and
apparently conclusive arguments, that even in the case of mercury such
a limit exists; much more he conceived it to be certain that our
atmosphere does not contain the vapour of the fixed constituents of the
earth's crust. This question, I may say, is likely to remain an open one.
Dr. Rankine, for example, has lately drawn attention to the odour of
certain metals; whence comes this odour, if it be not from the vapour of
the metal?
In 1825 Faraday became a member of a committee, to which Sir John
Herschel and Mr. Dollond also belonged, appointed by the Royal
Society to examine, and if possible improve, the manufacture of glass
for optical purposes. Their experiments continued till 1829, when the
account of them constituted the subject of a 'Bakerian Lecture.' This
lectureship, founded in 1774 by Henry Baker, Esq., of the Strand,
London, provides that every year a lecture shall be given before the
Royal Society, the sum of four pounds being paid to the lecturer. The

Bakerian Lecture, however, has long since passed from the region of
pay to that of honour, papers of mark only being chosen for it by the
council of the Society. Faraday's first Bakerian Lecture, 'On the
Manufacture of Glass for Optical Purposes,' was delivered at the close
of 1829. It is a most elaborate and conscientious description of
processes, precautions, and results: the details were so exact and so
minute, and the paper consequently so long, that three successive
sittings of the Royal Society were taken up by the delivery of the
lecture.[3] This glass did not turn out to be of important practical use,
but it happened afterwards to be the foundation of two of Faraday's
greatest discoveries.[4]
The experiments here referred to were commenced at the Falcon Glass
Works, on the premises of Messrs. Green and Pellatt, but Faraday could
not conveniently attend to them there. In 1827, therefore, a furnace was
erected in the yard of the Royal Institution; and it was at this time, and
with a view of assisting him at the furnace, that Faraday engaged
Sergeant Anderson, of the Royal Artillery, the respectable, truthful, and
altogether trustworthy man whose appearance here is so fresh in our
memories. Anderson continued to be the reverential helper of Faraday
and the faithful servant of this Institution for nearly forty years.[5]
In 1831 Faraday published a paper, 'On a peculiar class of Optical
Deceptions,' to which I believe the beautiful optical toy called the
Chromatrope owes its origin. In the same year he published a paper on
Vibrating Surfaces, in which he solved an acoustical problem which,
though of extreme simplicity when solved, appears to have baffled
many eminent men. The problem was to account for the fact that light
bodies, such as the seed of lycopodium, collected at the vibrating parts
of sounding plates, while sand ran to the nodal lines. Faraday showed
that the light bodies were entangled in the little whirlwinds formed in
the air over the places of vibration, and through which the heavier sand
was readily projected. Faraday's resources as an experimentalist were
so wonderful, and his delight in experiment was so great, that he
sometimes almost ran into excess in this direction. I have heard him say
that this paper on vibrating surfaces was too heavily laden with
experiments.
Footnotes to

Chapter 2
[1] The reader's attention is directed to the concluding paragraph of the
'Preface to the Second Edition written in December, 1869. Also to the
Life of Faraday by Dr. Bence Jones, vol.