CHEMISTRY.
Chemistry, having for its field the properties and changes of matter,
has excited more or less attention ever since men had the power to
observe, to think, and to experiment.
Some knowledge of chemistry must have existed among the ancients to have
enabled the Egyptians to smelt ores and work metals, to dye their
cloths, to make glass, and to preserve their dead from decomposition;
so, too, to this extent among the Phœnicians, the Israelites, the
Greeks and the Romans; and perhaps to a greater extent among the
Chinese, who added powder to the above named and other chemical
products. Aristotle speculated, and the alchemists of the middle ages
busied themselves in magic and guess-work. It reached the dignity of a
science in the seventeenth and eighteenth centuries, by the labours of
such men, in the former century, as Libavius, Van Helmont, Glauber,
Tachenius, Boyle, Lémery and Becher; Stahl, Boerhaave and Hamberg in
both; and of Black, Cavendish, Lavoisier, Priestley and others in the
eighteenth.
But so great have been the discoveries and inventions in this science
during the nineteenth century that any chemist of any previous age, if
permitted to look forward upon them, would have felt
“Like some watcher of the skies
When a new planet swims into his ken.”
Indeed, the chemistry of this century is a new world, of which all the
previous discoveries in that line were but floating nebulæ.
So vast and astonishingly fast has been the growth and development of
this science that before the century was two-thirds through its course
Watts published his _Dictionary of Chemistry_ in five volumes, averaging
a thousand closely printed pages, followed soon by a thousand-page
supplement; and it would have required such a volume every year since to
adequately report the progress of the science. Nomenclatures, formulas,
apparatuses and processes have all changed. It was deemed necessary to
publish works on _The New Chemistry_, and Professor J. P. Cooke is the
author of an admirable volume under that title.
We can, therefore, in this chapter only step from one to another of some
of the peaks that rise above the vast surrounding country, and note some
of the lesser objects as they appear in the vales below.
The leading discoveries of the century which have done so much to aid
Chemistry in its giant strides are the atomic and molecular theories,
the mechanics of light, heat, and electricity, the correlation and
conservation of forces, their invariable quantity, and their
indestructibility, spectrum analysis and the laws of chemical changes.
John Dalton, that humble child of English north-country Quaker stock,
self-taught and a teacher all his life, in 1803 gave to the world his
atomic theory of chemistry, whereby the existence of matter in ultimate
atoms was removed from the region of the speculation of certain ancient
philosophers, and established on a sure foundation.
The question asked and answered by Dalton was, what is the relative
weight of the atoms composing the elementary bodies?
He discovered that one chemical element or compound can combine with
another chemical element, to form a new compound, in two different
proportions by weight, which stand to each other in the simple ratio of
one to two; and at the same time he published a table of the _Relative
weight of the ultimate particles of Gaseous and other Bodies_. Although
the details of this table have since been changed, the principles of his
discovery remain unchanged. Says Professor Roscoe:
“Chemistry could hardly be said to exist as a science before the
establishment of the laws of combination in multiple proportions, and
the subsequent progress of chemical science materially depended upon
the determination of these combined proportions or atomic weights of
the elements first set up by Dalton. So that among the founders of our
science, next to the name of the great French Philosopher, Lavoisier,
will stand in future ages the name of John Dalton, of Manchester.”
Less conspicuous but still eminently useful were his discoveries and
labours in other directions, in the expansion of gases, evaporation,
steam, etc.
Wollaston and Gay-Lussac, both great chemists, applied Dalton’s
discovery to wide and most important fields in the chemical arts.
Also contemporaneous with Dalton was the great German chemist,
Berzelius, who confirmed and extended the discoveries of Dalton. More
than this, it has been said of Berzelius:
“In him were united all the different impulses which have advanced the
science since the beginning of the present epoch. The fruit of his
labors is scattered throughout the entire domain of the science.
Hardly a substance exists to the knowledge of which he has not in some
way contributed. A direct descendant of the school of his countryman,
Bergman, he was especially renowned as an analyst. No chemist has
determined by direct experiment the composition of a greater number of
substances. No one has exerted a greater influence in extending the
field of analytical chemistry.”
As to light, the great Huygens, the astronomer and mathematician, the
improver of differential calculus and of telescopes, the inventor of the
pendulum clock, chronometers, and the balance wheel to the watch, and
discoverer of the laws of the double refraction of light and of
polarisation, had in the 17th century clearly advanced the idea that
light was propagated from luminous bodies, not as a stream of particles
through the air but in waves or vibrations of ether, which is a
universal medium extending through all space and into all bodies. This
fundamental principle now enters into the explanation of all the
phenomena of light.
Newton in the next century, with the prism, decomposed light, and in a
darkened chamber reproduced all the colours and tints of the rainbow.
But there were dark lines in that beam of broken sunlight which Newton
did not notice.
It was left to Joseph von Fraunhofer, a German optician, and to the 19th
century, and nearly one hundred years after Newton’s experiments with
the prism, to discover, with finer prisms that he had made, some 590 of
these black lines crossing the solar spectrum. What they were he did not
know, but conjectured that they were caused by something which existed
in the sun and stars and not in our air. But from that time they were
called Fraunhofer’s dark lines.
From the vantage ground of these developments we are now enabled to step
to that mountain peak of discovery from which the sun and stars were
looked into, their elements portrayed, their very motions determined,
and their brotherhood with the earth, in substance, ascertained.
The great discovery of the cause of Fraunhofer’s dark bands in the
broken sunlight was made by Gustave Robert Kirchoff, a German physician,
in his laboratory in Heidelberg, in 1860, in conjunction with his fellow
worker, Robert Bunsen.
Kirchoff happened to let a solar ray pass through a flame coloured with
sodium, and through a prism, so that the spectrum of the sun and the
flame fell one upon another. It was expected that the well known yellow
line of sodium would come out in the solar spectrum, but it was just the
opposite that took place. Where the bright yellow line should have
fallen appeared a dark line.
With this observation was coupled the reflection that heat passes from a
body of a higher temperature to one of a lower, and not inversely.
Experiments followed: iron, sodium, copper, etc., were heated to
incandescence and their colours prismatically separated. These were
transversed with the same colours of other heated bodies, and the latter
were absorbed and rendered black. Kirchoff then announced his law that
all bodies absorb chiefly those colours which they themselves emit.
Therefore these vapours of the sun which were rendered in black lines
were so produced by crossing terrestrial vapors of the same nature.
Thus by the prism and the blowpipe were the same substances found in the
sun, the stars, and the earth. The elements of every substance submitted
to the process were analysed, and many secrets in the universe of matter
were revealed.
Young, of America, invented a splendid combination of spectroscope and
telescope, and Huggins of England was the first to establish by spectrum
analysis the approach and retreat of the stars.
It was prior to this time that those wonderful discoveries and labours
were made which developed the true nature of heat, which demonstrated
the kinship and correlation of the forces of Nature, their conservation,
or property of being converted one into another, and the
indestructibility of matter, of which force is but another name.
The first demonstrations as to the nature of heat were given by the
American Count Rumford, and then by Sir Humphry Davy, just at the close
of the 18th century, and then followed in this the brilliant labours and
discoveries of Mayer and Helmholtz of Germany, Colding of Denmark, and
Joule, Grove, Faraday, Sir William Thomson of England, of Henry, Le
Conte and Martin of America, as to the correlation and convertibility of
all the forces.
The French revolution, and the Napoleonic wars, isolating France and
exhausting its resources, its chemists were appealed to devote their
genius and researches to practical things; to the munitions of war, the
rejuvenation of the soil, the growing of new crops, like the sugar beet,
and new manufacturing products.
Lavoisier had laid deep and broad in France the foundations of
chemistry, and given the science nomenclature that lasted a century. So
that the succeeding great teachers, Berthollet, Guyton, Fourcroy and
their associates, and the institutions of instruction in the sciences
fostered by them, and inspired in that direction by Napoleon, bent their
energies in material directions, and a tremendous impulse was thus given
to the practical application of chemistry to the arts and manufactures
of the century.
The same spirit, to a less extent, however, manifested itself in
England, and as early as 1802 we find Sir Humphry Davy beginning his
celebrated lectures on the _Elements of Agricultural Chemistry_ before a
board of agriculture, a work that has passed through many editions in
almost every modern language.
When the fact is recalled that agricultural chemistry embraces the
entire natural science of vegetable and animal production, and includes,
besides, much of physics, meteorology and geology, the extent and
importance of the subject may be appreciated; and yet such appreciation
was not manifested in a practical manner until the 19th century. It was
only toward the end of the 18th century that the vague and ancient
notions that air, water, oil and salt formed the nutrition of plants,
began to be modified. Davy recognized and explained the beneficial
fertilizing effects of ammonia, and analysed and explained numerous
fertilizers, including guano. It is due to his discoveries and
publications, combined with those of the eminent men on the continent,
above referred to, that agricultural chemistry arose to the dignity of a
science. The most brilliant, eloquent and devoted apostle of that
science who followed Davy was Justus von Liebig of Germany, who was born
in Darmstadt in 1803, the year after Davy commenced his lectures in
England. It was in response to the British Association for the
Advancement of Science that he gave to the world his great publications
on _Chemistry in its application to Agriculture, Commerce, Physiology,
and Pathology_, from which great practical good resulted the world over.
One of his favorite subjects was that of fermentation, and this calls up
the exceedingly interesting discoveries in the nature of alcohol, yeast,
mould--aging malt, wines and beer--and their accompanying beneficial
results.
In one of Huxley’s charming lectures--such as he delighted to give
before a popular audience--delivered in 1871, at Manchester, on the
subject of “Yeast,” he tells how any liquid containing sugar, such as a
mixture of honey and water, if left to itself undergoes the peculiar
change we know as fermentation, and in the process the scum, or thicker
muddy part that forms on top, becomes yeast, carbonic acid gas escapes
in bubbles from the liquid, and the liquid itself becomes spirits of
wine or alcohol. “Alcohol” was a term used until the 17th century to
designate a very fine subtle powder, and then became the name of the
subtle spirit arising from fermentation. It was Leeuwenhoek of Holland
who, two hundred years ago, by the use of a fine microscope he invented,
first discovered that the muddy scum was a substance made up of an
enormous multitude of very minute grains floating separately, and in
lumps and in heaps, in the liquid. Then, in the next century the
Frenchman, Cagniard de la Tour, discovered that these bodies grew to a
certain size and then budded, and from the buds the plant multiplied;
and thus that this yeast was a mass of living plants, which received in
science the name of “torula,” that the yeast plant was a kind of fungus
or mould, growing and multiplying. Then came Fabroni, the French
chemist, at the end of the 18th century, who discovered that the yeast
plant was of bag-like form, or a cell of woody matter, and that the cell
contained a substance composed of carbon, hydrogen, oxygen and nitrogen.
This was a vegeto-animal substance, having peculiarities of “animal
products.”
Then came the great chemists of the 19th century, with their delicate
methods of analysis, and decided that this plant in its chief part was
identical with that element which forms the chief part of our own blood.
That it was protein, a substance which forms the foundation of every
animal organism. All agreed that it was the yeast plant that fermented
or broke up the sugar element, and produced the alcohol. Helmholtz
demonstrated that it was the minute particles of the solid part of the
plant that produced the fermentation, and that such particles must be
growing or alive, to produce it. From whence sprang this wonderful
plant--part vegetable, part animal? By a long series of experiments it
was found that if substances which could be fermented were kept entirely
closed to the outer air, no plant would form and no fermentation take
place. It was concluded then, and so ascertained, that the torulae in
the plant proceeded from the torulae in the atmosphere, from “gay motes
that people the sunbeams.” Concerning just how the torulae broke up or
fermented the sugar, great chemists have differed.
After the discovery that the yeast was a plant having cells formed of
the pure matter of wood, and containing a semi-fluid mass identical with
the composition which constitutes the flesh of animals, came the further
discovery that all plants, high and low, are made up of the same kind of
cells, and their contents. Then this remarkable result came out, that
however much a plant may otherwise differ from an animal, yet, in
essential constituents the cellular constructure of animal and plant is
the same. To this substance of energy and life, common in the minute
plant cell and the animal cell, the German botanist, Hugo von Mohl,
about fifty years ago gave the name “protoplasm.” Then came this
astounding conclusion, that this _protoplasm_ being common to both plant
and animal life, the essential difference consisted only in the manner
in which the cells are built up and are modified in the building.
And from that part of these great discoveries which revealed the fact
that the sugary element was infected, as it were, from the germs of the
air, producing fermentation and its results, arose that remarkable
theory of many diseases known as the “germ theory.” And, as it was found
in the yeast plant that only the solid part or particle of the plant
germinated fermentation and reaction, so, too, it has been found by the
germ theory that only the solid particle of the contagious matter can
germinate or grow the disease.
In this unfolding of the wonders of chemistry in the nineteenth century,
the old empirical walls between forces and organisms, and organic and
inorganic chemistry, are breaking down, and celestial and terrestrial
bodies and vapours, living beings, and growing plants are discovered to
be the evolution of one all-pervading essence and force. One is reminded
of the lines of Tennyson:
“Large elements in order brought
And tracts of calm from tempest made,
And world fluctuation swayed
In vassal tides that followed thought.
* * * * *
One God, one law, one element,
And one far-off divine event
To which the whole creation moves.”
In the class of alcohol and in the field of yeast, the work of Pasteur,
begun in France, has been followed by improvements in methods for
selecting proper ferments and excluding improper ones, and in improved
processes for aging and preserving alcoholic liquors by destroying
deleterious ferments. Takamine, in using as ferment, koji, motu and
moyashi, different forms of mould, and proposing to do entirely away
with malt in the manufacture of beer and whiskey, has made a noteworthy
departure. Manufacturing of malt by the pneumatic process, and stirring
malt during germination, are among the improvements.
_Carbonating._--The injecting of carbonic acid gas into various waters
to render them wholesome, and also into beers and wines during
fermentation, and to save delay and prevent impurities, are decided
improvements.
The immense improvements and discoveries in the character of soils and
fertilisers have already been alluded to. Hundreds of instruments have
been invented for measuring, analysing, weighing, separating,
volatilising and otherwise applying chemical processes to practical
purposes.
To the chemistry of the century the world is indebted for those devices
and processes for the utilisation and manufacture of many useful
products from the liquids and oils, sugar from cane and beets,
revivifying bone-black, centrifugal machinery for refining sugar, in
defecating it by chemicals and heat, in evaporating it in pans, in
separating starch and converting it into glucose, etc.
_Oils and Fats._--Up to within this century the vast amount of cotton
seed produced with that crop was a waste. Then by the process, first of
steaming the seed and expressing the oil, now by the process of
extraction by the aid of volatile solvents, and casting off the solvents
by distillation, an immensely valuable product has been obtained.
The utilising of oils in the manufacture of oilcloth and linoleum and
rubber, has become of great commercial value. Formerly sulphur was the
vulcanising agent, now chloride of sulphur has been substituted for pure
sulphur.
Steam and the distillation processes have been applied with great
success to the making of glycerine from fat and from soap underlye and
in extracting fat from various waste products.
_Bleaching and Dyeing._--Of course these arts are very old, but the old
methods would not be recognised in the modern processes; and those who
lived before the century knew nothing of the magnificent colours, and
certain essences, and sweet savours that can be obtained from the black,
hand-soiling pieces of coal. In the making of illuminating gas, itself a
finished chemical product of the century, a vast amount of once wasted
products, especially coal tar, are now extensively used; and from coal
tar and the residuum of petroleum oils, now come those splendid aniline
dyes which have produced such a revolution in the world of colours. The
saturation of sand by a dye and its application to fabrics by an air
blast; the circulation of the fluid colors, or of fluids for bleaching
or drying, or oxidising, through perforated cylinders or cops on which
the cloths are wound; devices for the running of skeins through dyes,
the great improvements in carbon dyes and kindred colours, the processes
of making the colours on the fibre, and the perfumes made by the
synthetic processes, are among the inventions in this field.
The space that a list of the new chemical products of this age and their
description would fill, has already been indicated by reference to the
great dictionary of Watts. Some of the electro-chemical products will be
hereinafter referred to in the Chapter on Electricity, and the chemistry
of Metallurgy will be treated under the latter topic.
_Electro-chemical Methods._--Space will only permit it to be said that
these methods are now employed in the production of a large number of
elements, by means of which very many of them which were before mere
laboratory specimens, have now become cheap and useful servants of
mankind in a hundred different ways; such as aluminium, that light and
non-corrosive metal, reduced from many dollars an ounce a generation
ago, to 30 and 40 cents a pound now; carborundum, largely superseding
emery and diamond dust as an abradant; artificial diamonds; calcium
carbide, from which the new illuminating acetylene gas is made;
disinfectants of many kinds; pigments, chromium, manganese, and
chlorates by the thousand tons. The most useful new chemical processes
are those used in purifying water sewage and milk, in electroplating
metals and other substances, in the application of chemicals to the fine
arts, in extracting grease from wool, and the making of many useful
products from the waste materials of the dumps and garbage banks.
_Medicines and Surgery._--One hundred years ago, the practice of
medicine was, in the main, empirical. Certain effects were known to
usually follow the giving of certain drugs, or the application of
certain measures, but why or how these effects were produced, was
unknown. The great steps forward have been made upon the true scientific
foundation established by the discoveries and inventions in the fields
of physics, chemistry and biology. The discovery of anaesthetics and
their application in surgery and the practice of medicine, no doubt
constitutes the leading invention of the century in this field.
Sir Humphry Davy suggested it in 1800, and Dr. W. T. Morton was the
first to apply an anaesthetic to relieve pain in a surgical operation,
which he did in a hospital in Boston in 1846. Both its original
suggestion and application were also claimed by others.
Not only relief from intense pain to the patient during the operation,
but immense advantages are gained by the long and careful examination
afforded of injured or diseased parts, otherwise difficult or impossible
in a conscious patient.
The exquisite pain and suffering endured previous to the use of
anaesthetics often caused death by exhaustion. Many delicate operations
can now be performed for the relief of long-continued diseases which
before would have been hazardous or impossible. How many before suffered
unto death long-drawn-out pain and disease rather than submit to the
torture of the knife! How many lives have been saved, and how far
advanced has become the knowledge of the human body and its painful
diseases, by this beneficent remedy!
Inventions in the field of medicine consist chiefly in those innumerable
compositions and compounds which have resulted from chemical
discoveries. Gelatine capsules used to conceal unpalatable remedies may
be mentioned as a most acceptable modern invention in this class.
Inventions and discoveries in the field of surgery relate not only to
instrumentalities but processes. The antiseptic treatment of wounds, by
which the long and exhausting suppuration is avoided, is among the most
notable of the latter. In instruments vast improvements have been made;
special forms adapted for operation in every form of injury; in
syringes, especially hypodermic, those used for subcutaneous injections
of liquid remedies; inhalers for applying medicated vapours and devices
for applying volatile anaesthetics, and devices for atomising and
spraying liquids. In the United States alone about four thousand patents
have been granted for inventions in surgical instruments.
_Dentistry._--This art has been revolutionised during the century. Even
in the time of Herodotus, one special set of physicians had the
treatment of teeth; and artificial teeth have been known and used for
many ages, but all seems crude and barbarous until these later days. In
addition to the use of anaesthetics, improvements have been made in
nearly every form of dental instruments, such as forceps, dental
engines, pluggers, drills, hammers, etc., and in the means and materials
for making teeth. Later leading inventions have reference to utilising
the roots of destroyed teeth as supports on which to form bridges to
which artificial teeth are secured, and to crowns for decayed teeth that
still have a solid base.
There exists no longer the dread of the dentist’s chair unless the
patient has neglected too long the visit. Pain cannot be all avoided,
but it is ameliorated; and the new results in workmanship in the saving
and in the making of teeth are vast improvements over the former
methods.