"I need not point out ... the difference in the perceptive powers of
the eye and the ear, and the facility and clearness with which the
first of these organs conveys ideas to the mind--ideas which, being
thus gained, are held far more retentively and firmly in the memory
than when introduced by the ear.... Apparatus, therefore, is an
essential part of every lecture in which it can be introduced.... When
... apparatus is to be exhibited, some kind of order should be
observed in the arrangement of them on the lecture-table. Every
particular part illustrative of the lecture should be in view, no one
thing should hide another from the audience, nor should anything stand
in the way of or obstruct the lecturer. They should be so placed, too,
as to produce a kind of uniformity in appearance. No one part should
appear naked and another crowded, unless some particular reason
exists and makes it necessary to be so."
On October 13, 1813, Faraday left the Royal Institution, in order to
accompany Sir Humphry Davy in a tour on the Continent. His journal
gives some interesting details, showing the inconveniences of foreign
travel at that time. Sir Humphry Davy took his carriage with him in
pieces, and these had to be put together after escaping the dangers of
the French custom-house on the quay at Morlaix, two years before the
battle of Waterloo.
One apparently trivial incident somewhat marred Faraday's pleasure
throughout this journey. It was originally intended that the party
should comprise Sir Humphry and Lady Davy, Faraday, and Sir Humphry's
valet, but at the last moment that most important functionary declined
to leave his native shores. Davy then requested Faraday to undertake
such of the duties of valet as were essential to the well-being of the
party, promising to secure the services of a suitable person in Paris.
But no eligible candidate appeared for the appointment, and thus
Faraday had throughout to take charge of domestic affairs as well as
to assist in experiments. Had there been only Sir Humphry and himself,
this would have been no hardship. Sir Humphry had been accustomed to
humble life in his early days; but the case was different with his
lady, and, apparently, Faraday was more than once on the point of
leaving his patron and returning home alone. A circumstance which
occurred at Geneva illustrates the position of affairs. Professor E.
de la Rive invited Sir Humphry and Lady Davy and Faraday to dinner.
Sir Humphry could not go into society with one who, in some respects,
acted as his valet. When this point was represented to the professor,
he replied that he was sorry, as it would necessitate his giving
another dinner-party. Faraday subsequently kept up a correspondence
with De la Rive, and continued it with his son. In writing to the
latter he says, in speaking of Professor E. de la Rive, that he was
"the first who personally at Geneva, and afterwards by correspondence,
encouraged and by that sustained me."
At Paris Faraday met many of the most distinguished men of science of
the time. One morning Ampere, Clement, and Desormes called on Davy, to
show him some iodine, a substance which had been discovered only about
two years before, and Davy, while in Paris, and afterwards at
Montpellier, executed a series of experiments upon it. After three
months' stay, the party left Paris for Italy, _via_ Montpellier, Aix,
and Nice, whence they crossed the Col de Tende to Turin. The transfer
of the carriage and baggage across the Alps was effected by a party of
sixty-five men, with sledges and a number of mules. The description of
the journey, as recorded in Faraday's diary, makes us respect the
courage of an Englishman who, in the early part of this century, would
attempt the conveyance of a carriage across the Alps in the winter.
"From Turin we proceeded to Genoa, which place we left afterwards in
an open boat, and proceeded by sea towards Lerici. This place we
reached after a very disagreeable passage, and not without
apprehensions of being overset by the way. As there was nothing there
very enticing, we continued our route to Florence; and, after a stay
of three weeks or a month, left that fine city, and in four days
arrived here at Rome." The foregoing is from Faraday's letter to his
mother. At Florence a good deal of time was spent in the Academia del
Cimento. Here Faraday saw the telescope with which Galileo discovered
Jupiter's satellites, with its tube of wood and paper about three feet
and a half long, and simple object-glass and eye-glass. A red velvet
electric machine with a rubber of gold paper, Leyden jars pierced by
the discharge between their armatures, the first lens constructed by
Galileo, and a number of other objects, were full of interest to the
recently enfranchised bookbinder's apprentice; but it was the great
burning-glass of the grand-duke which was the most serviceable of all
the treasures of the museum. With this glass--which consisted of two
convex lenses about three feet six inches apart, the first lens having
a diameter of about fourteen or fifteen inches, and the second a
diameter of three inches--Davy succeeded in burning several diamonds
in oxygen gas, and in proving that the diamond consists of little else
than carbon. In 1818 Faraday published a paper on this subject in the
_Quarterly Journal of Science_. At Genoa some experiments were made
with the torpedo, but the specimens caught were very small and weak,
and their shocks so feeble that no definite results were obtained. At
Rome Davy attempted to repeat an experiment of Signor Morrichini,
whereby a steel needle was magnetized by causing the concentrated
violet and blue rays from the sun to traverse the needle from the
middle to the north end several times. The experiment did not succeed
in the hands of Davy and Faraday, and it was left to the latter to
discover a relation between magnetism and light. From Rome they
visited Naples and ascended Vesuvius, and shortly afterwards left
Italy for Geneva. In the autumn of 1814 they returned from Switzerland
through Germany, visiting Berne, Zurich, the Tyrol, Padua, Venice, and
Bologne, to Florence, where Davy again carried out some chemical
investigations in the laboratory of the academy. Thence they returned
to Rome, and in the spring went on to Naples, and again visited
Vesuvius, returning to England in April, _via_ Rome, the Tyrol,
Stuttgart, Brussels, and Ostend.
A fortnight after his return from the Continent Faraday was again
assistant at the Royal Institution, but with a salary of thirty
shillings a week. His character will be sufficiently evident from the
quotations which have been given from his diary and letters.
Henceforth we must be mainly occupied with the consideration of his
scientific work.
In January, 1816, he gave his first lecture to the City Philosophical
Society. In a lecture delivered shortly afterwards before the same
society, the following passage, which gives an idea of one of the
current beliefs of the time, occurs:--
"The conclusion that is now generally received appears to be that
light consists of minute atoms of matter of an octahedral form,
possessing polarity, and varying in size or in velocity....
"If now we conceive a change as far beyond vaporization as that is
above fluidity, and then take into account also the proportional
increased extent of alteration as the changes rise, we shall, perhaps,
if we can form any conception at all, not fall far short of radiant
matter;[6] and as in the last conversion many qualities were lost, so
here also many more would disappear.
[Footnote 6: Not Crookes's.]
"It was the opinion of Newton, and of many other distinguished
philosophers, that this conversion was possible, and continually going
on in the processes of nature, and they found that the idea would bear
without injury the application of mathematical reasoning--as regards
heat, for instance. If assumed, we must also assume the simplicity of
matter; for it would follow that all the variety of substances with
which we are acquainted could be converted into one of three kinds of
radiant matter, which again may differ from one another only in the
size of their particles or their form. The properties of known bodies
would then be supposed to arise from the varied arrangements of their
ultimate atoms, and belong to substances only as long as their
compound nature existed; and thus variety of matter and variety of
properties would be found co-essential. The simplicity of such a
system is singularly beautiful, the idea grand and worthy of Newton's
approbation. It was what the ancients believed, and it may be what a
future race will realize."
In the closing words of his fifth lecture to the City Philosophical
Society, Faraday said:--
"The philosopher should be a man willing to listen to every
suggestion, but determined to judge for himself. He should not be
biassed by any appearances; have no favourite hypothesis; be of no
school; and in doctrine have no master. He should not be a respecter
of persons, but of things. Truth should be his primary object. If to
these qualities be added industry, he may indeed hope to walk within
the veil of the temple of nature."
Many years afterwards he stated that, of all the suggestions to which
he had patiently listened after his lectures at the Royal Institution,
only one proved on investigation to be of any value, and that led to
the discovery of the "extra current" and the whole subject of
self-induction.
Faraday always kept a note-book, in which he jotted down any thoughts
which occurred to him in reference to his work, as well as extracts
from books or other publications which attracted his attention. He
called it his "commonplace-book." Many of the queries which he here
took note of he subsequently answered by experiment. For example:--
"Query: the nature of sounds produced by flame in tubes."
"Convert magnetism into electricity."
"General effects of compression, either in condensing gases or
producing solutions, or even giving combinations at low temperature."
"Do the pith-balls diverge by the disturbance of electricity through
mutual induction or not?"
Speaking of this book, he says, "I already owe much to these notes,
and think such a collection worth the making by every scientific man.
I am sure none would think the trouble lost after a year's
experience."