By JOHN TIMBS, F.S.A.
(1778-1829)
[Illustration: Sir Humphry Davy.]
The boyhood of Davy has been sketched in some of the most
fascinating pieces of biography ever written: the annals of science
do not furnish us with any record that equals the school-days and
self-education of the boy, Humphry, in popular interest; and, unlike
many bright mornings, this commencement in a few years led to a
brilliant meridian, and, by a succession of discoveries,
accomplished more in relation to change of theory and extension of
science, than in the most ardent and ambitious moments of youth he
could either hope to effect or imagine possible.
Humphry Davy was born at Penzance, in 1778; was a healthy, strong,
and active child, and could speak fluently before he was two years
old; copied engravings before he learned to write, and could recite
part of the "Pilgrim's Progress" before he could well read it. At
the age of five years, he could gain a good account of the contents
of a book while turning over the leaves; and he retained this
remarkable faculty through life. He excelled in telling stories to
his playmates; loved fishing, and collecting, and painting birds and
fishes; he had his own little garden; and recorded his impressions
of romantic scenery in verse of no ordinary merit. To his
self-education, however, he owed almost everything. He studied with
intensity mathematics, metaphysics, and physiology; before he was
nineteen he began to study chemistry, and in four months proposed a
new hypothesis on heat and light, to which he won over the
experienced Dr. Beddoes. With his associate, Gregory Watt (son of
the celebrated James Watt) he collected specimens of rocks and
minerals. He made considerable progress in medicine; he experimented
zealously, especially on the effects of the gases in respiration; at
the age of twenty-one he had breathed nitrous oxide, and nearly lost
his life from breathing carburetted hydrogen. Next year he commenced
the galvanic experiments which led to some of his greatest
discoveries. In 1802 he began his brilliant scientific career at the
Royal Institution, where he remained till 1812; here he constructed
his great voltaic battery of 2,000 double plates of copper and zinc,
and commenced the mineralogical collection now in the Museum. His
lectures were often attended by one thousand persons: his youth, his
simplicity, his natural eloquence, his chemical knowledge, his happy
illustrations and well-conducted experiments, and the auspicious
state of science, insured Davy great and instant success.
The enthusiastic admiration with which he was hailed can hardly be
imagined now. Not only men of the highest rank--men of science, men of
letters, and men of trade--but women of fashion and blue-stockings,
old and young, pressed into the theatre of the Institution to cover
him with applause. His greatest labors were his discovery of the
decomposition of the fixed alkalies, and the re-establishment of the
simple nature of chlorine; his other researches were the investigation
of astringent vegetables in connection with the art of tanning; the
analysis of rocks and minerals in connection with geology; the
comprehensive subject of agricultural chemistry; and galvanism and
electro-chemical science. He was also an early, but unsuccessful,
experimenter in the photographic art.
Of the lazy conservative spirit and ludicrous indolence in science,
which at this time attempted to hoodwink the public, a quaint
instance is recorded of a worthy professor of chemistry at Aberdeen.
He had allowed some years to pass since Davy's brilliant discovery
of potassium and its congeneric metals, without a word about them in
his lectures. At length the learned doctor was concussed by his
colleagues on the subject, and he condescended to notice it. "Both
potash and soda are now said to be metallic oxides," said he; "the
oxides, in fact, of two metals, called potassium and sodium by the
discoverer of them, one Davy, in London, a verra troublesome person
in chemistry."
Turn we, however, to the brightest event in our chemical
philosopher's career. By his unrivalled series of practical
discoveries, Davy acquired such a reputation for success among his
countrymen, that his aid was invoked on every great occasion. The
properties of fire-damp, or carburetted hydrogen, in coal-mines had
already been ascertained by Dr. Henry. When this gas is mingled in
certain proportions with atmospheric air, it forms a mixture which
kindles upon the contact of a lighted candle, and often explodes
with tremendous violence, killing the men and horses, and projecting
much of the contents of the mine through the shafts or apertures
like an enormous piece of artillery. At this time, a detonation of
fire-damp occurred within a coal-mine in the north of England, so
dreadful that it destroyed more than a hundred miners. A committee
of the proprietors besought our chemist to provide a method of
preparing for such tremendous visitations; and he did it. He tells
us that he first turned his attention particularly to the subject in
1815; but he must have been prepared for it by the researches of his
early years. Still, there appeared little hope of finding an
efficacious remedy. The resources of modern mechanical science had
been fully applied in ventilation. The comparative lightness of
fire-damp was well understood; every precaution was taken to
preserve the communications open; and the currents of air were
promoted or occasioned, not only by furnaces, but likewise by
air-pumps and steam apparatus. We may here mention that, for giving
light to the coal-miner or pitman, where the fire-damp was
apprehended, the primitive contrivance was a steel-mill, the light
of which was produced by contact of a flint with the edge of a wheel
kept in rapid motion. A "safety-lamp" had already, in 1813, been
constructed by Dr. Clanny, the principle of which was forcing in air
through water by bellows; but the machine was ponderous and
complicated, and required a boy to work it. M. Humboldt had
previously, in 1796, constructed a lamp for mines upon the same
principle as that of Dr. Clanny.
Davy, having conceived that flame and explosion may be regulated and
arrested, began a minute chemical examination of fire-damp. He found
that carburetted-hydrogen gas, even when mixed with fourteen times
its bulk of atmospheric air, was still explosive. He ascertained
that explosions of inflammable gases were incapable of being passed
through long, narrow metallic tubes; and that this principle of
security was still obtained by diminishing their length and diameter
at the same time, and likewise diminishing their length and
increasing their number, so that a great number of small apertures
would not pass explosion when their depth was equal to their
diameter. This fact led to trials upon sieves of wire-gauze; he
found that if a piece of wire-gauze was held over the flame of a
lamp, or coal-gas, it prevented the flame from passing; and he
ascertained that a flame confined in a cylinder of very fine
wire-gauze did not explode even in a mixture of oxygen and hydrogen,
but that the gases burned in it with great vivacity. These
experiments served as the basis of the safety-lamp.
Sir Humphry Davy presented his first communication respecting his
discovery of the safety-lamp to the Royal Society in 1815. This was
followed by a series of papers, crowned by that read on January 11,
1816, when the principle of the safety-lamp was announced, and Sir
Humphry presented to the society a model made by his own hands,
which is to this day preserved in the collection of the Royal
Society at Burlington House.
There have been several modifications of the safety-lamp, and the
merit of the discovery has been claimed by others, among whom was
Mr. George Stephenson; but the question was set at rest in 1817 by
an examination, attested by Sir Joseph Banks, P.R.S., Mr. Brande,
Mr. Hatchett, and Dr. Wollaston, and awarding the independent merit
to Davy.
It should be explained that Stephenson's lamp was formed on the
principle of admitting the fire-damp by narrow tubes, and "in such
small detached portions that it would be consumed by combustion."
The two lamps were doubtless distinct inventions; though Davy, in
all justice, appears to be entitled to precedence, not only in point
of date, but as regards the long chain of inductive reasoning
concerning the nature of flame by which his result was arrived at.
Meanwhile, the Report by the Parliamentary Committee "cannot admit
that the experiments (made with the lamp) have any tendency to
detract from the character of Sir Humphry Davy, or to disparage the
fair value placed by himself upon his invention. The improvements
are probably those which longer life and additional facts would have
induced him to contemplate as desirable, and of which, had he not
been the inventor, he might have become the patron."
"I value it," Davy used to say, with the kindliest exultation, "more
than anything I ever did; it was the result of a great deal of
investigation and labor; but if my directions be attended to, it
will save the lives of thousands of poor men."
The principle of the invention may be thus summed up: In the
safety-lamp, the mixture of the fire-damp and atmospheric air within
the cage of wire-gauze explodes upon coming in contact with the
flame; but the combustion cannot pass through the wire-gauze; and
being there imprisoned, cannot impart to the explosive atmosphere of
the mine any of its force. This effect has been attributed to the
cooling influence of the metal; but, since the wires may be brought
to a degree of heat but little below redness without igniting the
fire-damp, this does not appear to be the cause.
Professor Playfair has elegantly characterized the safety-lamp of
Davy as a present from philosophy to the arts, a discovery in no
degree the effect of accident or chance, but the result of patient
and enlightened research, and strongly exemplifying the great use of
an immediate and constant appeal to experiment. After characterizing
the invention as the _shutting-up in a net of the most slender
texture_ of a most violent and irresistible force, and a power that
in its tremendous effects seems to emulate the lightning and the
earthquake, Professor Playfair thus concludes: "When to this we add
the beneficial consequences, and the saving of the lives of men, and
consider that the effects are to remain as long as coal continues to
be dug from the bowels of the earth, it may be fairly said that
there is hardly in the whole compass of art or science a single
invention of which one would rather wish to be the author.... This,"
says Professor Playfair, "is exactly such a case as we should choose
to place before Bacon, were he to revisit the earth; in order to
give him, in a small compass, an idea of the advancement which
philosophy has made since the time when he had pointed out to her
the route which she ought to pursue."
Honors were showered upon Davy. He received from the Royal Society
the Copley, Royal, and Rumford Medals, and several times delivered
the Bakerian Lecture. He also received Napoleon's prize for the
advancement of galvanic researches from the French Institute. The
invention of the safety-lamp brought him the public gratitude of the
united colliers of Whitehaven, of the coal proprietors of the north
of England, of the grand jury of Durham, of the Chamber of Commerce
at Mons, of the coal-miners of Flanders, and, above all, of the
coal-owners of the Wear and the Tyne, who presented him (it was his
own choice) with a dinner-service of silver worth £2,500. On the
same occasion, Alexander, the Emperor of all the Russias, sent him a
vase, with a letter of commendation. In 1817, he was elected to the
dignity of an associate of the Institute of France; next year, at
the age of forty, he was created a baronet.
Davy's discoveries form a remarkable epoch in the history of the
Royal Society during the early part of this century; and from 1821
to 1829 almost every volume of the _Transactions_ contains a
communication by him. He was president of the Royal Society from
1820 to 1827.
Fond of travel, geology, and sport, Davy visited, for the purpose of
mineralogy and angling, almost every county of England and Wales. He
was provided with a portable laboratory, that he might experiment
when he chose, as well as fish and shoot. In 1827, upon resigning
the presidency of the Royal Society, he retired to the continent; in
1829, at Geneva, his palsy-stricken body returned to the dust. They
buried him at Geneva, where a simple monument stands at the head of
the hospitable grave. There is a tablet to his memory in Westminster
Abbey; there is a monument at Penzance; and his widow founded a
memorial chemical prize in the University of Geneva. His public
services of plate, his imperial vases, his foreign prizes, his royal
medals, shall be handed down with triumph to his collateral
posterity as trophies won from the depths of nescience; but his
work, designed by his own genius, executed by his own hand, tracery
and all, and every single stone signalized by his own private mark,
indelible, characteristic, and inimitable--his work is the only
record of his name. How deeply are its foundations rooted in space,
and how lasting its materials for time!