In a work on the Decline of Science,
at a period when England has so recently lost two
of its brightest ornaments, I should hardly be excused
if I omitted to devote a few words to the names of
Wollaston and of Davy. Until the warm feelings
of surviving kindred and admiring friends shall be
cold as the grave from which remembrance vainly recalls
their cherished forms, invested with all the life
and energy of recent existence, the volumes of their
biography must be sealed. Their contemporaries
can expect only to read their eloge.
In habits of intercourse with both
those distinguished individuals, sufficiently frequent
to mark the curiously different structure of their
minds, I was yet not on such terms even with him I
most esteemed, as to view his great qualities through
that medium which is rarely penetrated by the eyes
of long and very intimate friendship.
Caution and precision were the predominant
features of the character of Wollaston, and those
who are disposed to reduce the number of principles,
would perhaps justly trace the precision which adorned
his philosophical, to the extreme caution which pervaded
his moral character. It may indeed be questioned
whether the latter quality will not in all persons
of great abilities produce the former.
Ambition constituted a far larger
ingredient in the character of Davy, and with the
daring hand of genius he grasped even the remotest
conclusions to which a theory led him. He seemed
to think invention a more common attribute than it
really is, and hastened, as soon as he was in possession
of a new fact or a new principle, to communicate it
to the world, doubtful perhaps lest he might not be
anticipated; but, confident in his own powers, he
was content to give to others a chance of reaping some
part of that harvest, the largest portion of which
he knew must still fall to his own share.
Dr. Wollaston, on the other hand,
appreciated more truly the rarity of the inventive
faculty; and, undeterred by the fear of being anticipated,
when he had contrived a new instrument, or detected
a new principle, he brought all the information that
he could collect from others, or which arose from
his own reflection, to bear upon it for years, before
he delivered it to the world.
The most singular characteristic of
Wollaston’s mind was the plain and distinct
line which separated what he knew from what he did
not know; and this again, arising from his precision,
might be traced to caution.
It would, however, have been visible
to such an extent in few except himself, for there
were very few so perfectly free from vanity and affectation.
To this circumstance may be attributed a peculiarity
of manner in the mode in which he communicated information
to those who sought it from him, which was to many
extremely disagreeable. He usually, by a few
questions, ascertained precisely how much the inquirer
knew upon the subject, or the exact point at which
his ignorance commenced, a process not very agreeable
to the vanity of mankind; taking up the subject at
this point, he would then very clearly and shortly
explain it.
His acquaintance with mathematics
was very limited. Many years since, when I was
an unsuccessful candidate for a professorship of mathematics,
I applied to Dr. W. for a recommendation; he declined
it, on the ground of its not being his pursuit.
I told him I asked it, because I thought it would
have weight, to which he replied, that it ought to
have none whatever. There is no doubt his view
was the just one. Yet such is the state of ignorance
which exists on these subjects, that I have several
times heard him mentioned as one of the greatest mathematicians
of the age. [This of course could only have happened
in England.] But in this as in all other points, the
precision with which he comprehended and retained
all he had ever learned, especially of the elementary
applications of mathematics to physics, was such,
that he possessed greater command over those subjects
than many of far more extensive knowledge.
In associating with Wollaston, you
perceived that the predominant principle was to avoid
error; in the society of Davy, you saw that it was
the desire to see and make known truth. Wollaston
never could have been a poet; Davy might have been
a great one.
A question which I put, successively,
to each of these distinguished philosophers, will
show how very differently a subject may be viewed
by minds even of the highest order.
About the time Mr. Perkins was making
his experiments on the compression of water, I was
much struck with the mechanical means he had brought
to bear on the subject, and was speculating on other
applications of it, which I will presently mention.
Meeting Dr. Wollaston one morning
in the shop of a bookseller, I proposed this question:
If two volumes of hydrogen and one of oxygen are
mixed together in a vessel, and if by mechanical pressure
they can be so condensed as to become of the same
specific gravity as water, will the gases under these
circumstances unite and form water? “What
do you think they will do?” said Dr. W. I
replied, that I should rather expect they would unite.
“I see no reason to suppose it,” said
he. I then inquired whether he thought the experiment
worth making. He answered, that he did not,
for that he should think it would certainly not succeed.
A few days after, I proposed the same
question to Sir Humphry Davy. He at once said,
“they will become water, of course;” and
on my inquiring whether he thought the experiment worth
making, he observed that it was a good experiment,
but one which it was hardly necessary to make, as
it must succeed.
These were off-hand answers, which
it might perhaps be hardly fair to have recorded,
had they been of persons of less eminent talent:
and it adds to the curiosity of the circumstance to
mention, that I believe Dr. Wollaston’s reason
for supposing no union would take place, arose from
the nature of the electrical relations of the two
gases remaining unchanged, an objection which did
not weigh with the philosopher whose discoveries had
given birth to it.
[The result of the experiment appeared,
and still appears to me, to be of the highest importance;
and I will shortly state the views with which it was
connected. The next great discovery in chemistry
to definite proportions, will be to find means of
forming all the simple unions of one atom with one,
with two, or with more of say other substance:
and it occurred to me that the gaseous bodies presented
the fairest chance of success; and that if wishing,
for instance, to unite four atoms of one substance
with one of another, we could, by mechanical means,
reduce the mixed gases to the same specific gravity
as the substance would possess which resulted from
their union, then either that such union would actually
take place, or the particles of the two substances
would be most favourably situated for the action of
caloric, electricity, or other causes, to produce the
combination. It would indeed seem to follow,
that if combination should take place under such circumstances,
then the most probable proportion in which the atoms
would unite, should be that which furnished a fluid
of the least specific gravity: but until the
experiments are made, it is by no means certain that
other combinations might not be produced.]
The singular minuteness of the particles
of bodies submitted by Dr. Wollaston to chemical analysis,
has excited the admiration of all those who have had
the good fortune to witness his experiments; and the
methods he employed deserve to be much more widely
known.
It appears to me that a great mistake
exists on the subject. It has been adduced as
one of those facts which prove the extraordinary acuteness
of the bodily senses of the individual, —a
circumstance which, if it were true, would add but
little to his philosophical character; I am, however,
inclined to view it in a far different light, and
to see in it one of the natural results of the admirable
precision of his knowledge.
During the many opportunities I have
enjoyed of seeing his minute experiments, I remember
but one instance in which I noticed any remarkable
difference in the acuteness of his bodily faculties,
either of his hearing, his sight, or of his sense of
smell, from those of other persons who possessed them
in a good degree. [This was at Mr. South’s observatory,
and the object was, the dots on the declination circle
of his equatorial; but, in this instance, Dr. Wollaston
did not attempt to teach me how to
see them.]
He never showed me an almost microscopic
wire, which was visible to his, and invisible to my
own eye: even in the beautiful experiments he
made relative to sounds inaudible to certain ears,
he never produced a tone which was unheard by mine,
although sensible to his ear; and I believe this will
be found to have been the case by most of those whose
minds had been much accustomed to experimental inquiries,
and who possessed their faculties unimpaired by illness
or by age.
It was a much more valuable property
on which the success of such inquiries depended.
It arose from the perfect attention which he could
command, and the minute precision with which he examined
every object. A striking illustration of the
fact that an object is frequently not seen, from
not knowing how to see it,
rather than from any defect in the organ of vision,
occurred to me some years since, when on a visit at
Slough. Conversing with Mr. Herschel on the
dark lines seen in the solar spectrum by Fraunhofer,
he inquired whether I had seen them; and on my replying
in the negative, and expressing a great desire to see
them, he mentioned the extreme difficulty he had had,
even with Fraunhofer’s description in his hand
and the long time which it had cost him in detecting
them. My friend then added, “I will prepare
the apparatus, and put you in such a position that
they shall be visible, and yet you shall look for
them and not find them: after which, while you
remain in the same position, I will instruct you how
to see them, and you shall see them, and not merely
wonder you did not see them before, but you shall find
it impossible to look at the spectrum without seeing
them.”
On looking as I was directed, notwithstanding
the previous warning, I did not see them; and after
some time I inquired how they might be seen, when
the prediction of Mr. Herschel was completely fulfilled.
It was this attention to minute phenomena
which Dr. Wollaston applied with such powerful effect
to chemistry. In the ordinary cases of precipitation
the cloudiness is visible in a single drop as well
as in a gallon of a solution; and in those cases where
the cloudiness is so slight, as to require a mass of
fluid to render it visible, previous evaporation,
quickly performed on slips of window glass, rendered
the solution more concentrated.
The true value of this minute chemistry
arises from its cheapness and the extreme rapidity
with which it can be accomplished: it may, in
hands like those of Wollaston, be used for discovery,
but not for measure. I have thought it more
necessary to place this subject on what I consider
its true grounds, for two reasons. In the first
place, I feel that injustice has been done to a distinguished
philosopher in attributing to some of his bodily senses
that excellence which I think is proved to have depended
on the admirable training of his intellectual faculties.
And, in the next place, if I have established the
fact, whilst it affords us better means of judging
of such observations as lay claim to an accuracy “More
than human,” it also opens, to the
patient inquirer into truth, a path by which he may
acquire powers that he would otherwise have thought
were only the gift of nature to a favoured few.