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 a.s.sociates, and the inst.i.tutions 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 pa.s.sed 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 a.n.a.lysed 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 a.s.sociation 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 sc.u.m, 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 sc.u.m was a substance made up of an enormous mult.i.tude 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 ma.s.s 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 a.n.a.lysis, 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 ma.s.s identical with the composition which const.i.tutes 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 const.i.tuents 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 va.s.sal tides that followed thought.

One G.o.d, one law, one element, And one far-off divine event To which the whole creation moves."

In the cla.s.s 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, a.n.a.lysing, 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 subst.i.tuted 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 s.p.a.ce 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._--s.p.a.ce 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 const.i.tutes 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 cla.s.s.

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.

CHAPTER VII.

STEAM AND STEAM ENGINES.

"Soon shall thy arm, unconquered steam! afar Drag the slow barge, or drive the rapid car; Or in wide waving wings expanded bear The flying chariot through the field of air."

Thus sang the poet prophet, the good Dr. Darwin of Lichfield, in the eighteenth century. Newcomen and Watt had not then demonstrated that steam was not unconquerable, but the hitching it to the slow barge and the rapid car was yet to come. It has come, and although the prophecy is yet to be rounded into fulfilment by the driving of the "flying chariot through the field of air," that too is to come.

The prophecy of the doctor poet was as suggestive of the practical means of carrying it into effect as were all the means proposed during the first seventeen centuries of the Christian Era for conquering steam and harnessing it as a useful servant to man.

Toys, speculations, dreams, observations, startling experiments, these often const.i.tute the framework on which is hung the t.i.tle of Inventor; but the nineteenth century has demanded a better support for that proud t.i.tle. He alone who first transforms his ideas into actual work and useful service in some field of man's labor, or clearly teaches others to do so, is now recognised as the true inventor. Tested by this rule there was scarcely an inventor in the field of steam in all the long stretches of time preceding the seventeenth century. And if there were, they had no recording scribes to embalm their efforts in history.

We shall never know how early man learned the wonderful power of the spirit that springs from heated water. It was doubtless from some sad experience in ignorantly attempting to put fetters on it.

The history of steam as a motor generally commences with reference to that toy called the aeolipile, described by Hero of Alexandria in a treatise on pneumatics about two centuries before Christ, and which was the invention of either himself or Ctesibius, his teacher.

This toy consisted of a globe pivoted on two supports, one of which was a communicating pipe leading into a heated cauldron of water beneath.

The globe was provided with two escape pipes on diametrically opposite sides and bent so as to discharge in opposite directions. Steam admitted into the globe from the cauldron escaped through the side pipes, and its pressure on these pipes caused the globe to rotate.

Hero thus demonstrated that water can be converted into steam and steam into work.

Since that ancient day Hero's apparatus has been frequently reinvented by men ignorant of the early effort, and the principle of the invention as well as substantially the same form have been put into many practical uses. Hero in his celebrated treatise described other devices, curious siphons and pumps. Many of them are supposed to have been used in the performance of some of the startling religious rites at the altars of the Greek priests.

From Hero's day the record drops down to the middle ages, and still it finds progress in this art confined to a few observations and speculations. William of Malmesbury in 1150 wrote something on the subject and called attention to some crude experiments he had heard of in Germany. Pa.s.sing from the slumber of the middle ages, we are a.s.sured by some Spanish historians that one Blasco de Garay, in 1543, propelled a ship having paddle wheels by steam at Barcelona. But the publication was long after the alleged event, and is regarded as apocryphal.

Observations became more acute in the sixteenth and seventeenth centuries, experiments more frequent, and publications more full and numerous.

Cardan Ramelli and Leonardo da Vinci, learned Italians, and the accomplished Prof. Jacob Besson of Orleans, France, all did much by their writings to make known theoretically the wonderful powers of steam, and to suggest modes of its practical operation, in the latter part of the sixteenth century.