The exports of wheat to foreign lands in 1898 were 148,231,261 bushels, worth $145,684,659, and the exports of wheat flour for the same year were 15,349,943 barrels, worth $69,263,718. The total yield of wheat in the United States for 1898 was 675,148,705 bushels.

With the fertile earth, and its prolific inventors, the United States has become the richest country in the world. What its future is to be no man may say, but its destiny is not yet fulfilled, and it is pregnant with potential possibilities.

CHAPTER XVII.

VULCANIZED RUBBER.

EARLY USE OF CAOUTCHOUC BY THE INDIANS--COLLECTION OF THE GUM--EARLY EXPERIMENTS FAILURES--GOODYEAR'S PERSISTENT EXPERIMENTS--NATHANIEL HAYWARD'S APPLICATION OF SULPHUR TO THE GUM--GOODYEAR'S PROCESS OF VULCANIZATION--INTRODUCTION OF HIS PROCESS INTO EUROPE--TRIALS AND IMPRISONMENT FOR DEBT--RUBBER SHOE INDUSTRY--GREAT EXTENT AND VARIETY OF APPLICATIONS--STATISTICS.

Most all important inventions have grown into existence by slow stages of development, and by successive contributions from many minds, not a few having descended by gradual processes of evolution from preceding centuries. Vulcanized rubber, however, is not of this cla.s.s. It belongs exclusively to the Nineteenth Century, and owes its existence to the tireless energy of one man. The value of the crude gum had been previously speculated upon, and for years attempts had been made to utilize it, but not until Goodyear invented his process of vulcanizing it did it have any real value. This process was an important, distinct and unique step, entirely the work of Mr. Goodyear, and it has never been superseded nor improved upon to any extent. Charles Goodyear was born in New Haven, December 29, 1800, and his life, beginning two days in advance of the Nineteenth Century, furnishes an extraordinary ill.u.s.tration of the struggles and trials of the inventor against adverse fortune, and is a pathetic example of self denial, indefatigable labor, and unrequited toil. Of feeble health, small stature, poor, and frequently in prison for debt, he made the development of this art the paramount object of his life, and with a pious faith and unfaltering courage for thirty years he devoted himself to this work. Money he cared nothing for, except in so far as it was necessary to carry on his work, and he died July 1, 1860, poor in this world's goods, but rich in the consciousness of the great benefit conferred by his invention upon the human race.

[Ill.u.s.tration: FIG. 160.--COLLECTING THE GUM.]

India rubber, or caoutchouc, as it is more properly called, is a concentrated gum derived from the evaporation of the milky juice of certain trees found in South America, Mexico, Central America and the East Indies. The South American variety is called _Jatropha elastica_, and the East Indian variety the _Ficus elastica_. The South American Indians called it _cahuchu_. The province of Para, south of the equator, in Brazil, furnishes the largest part and best quality of gum. The tree from which the gum exudes grows to the height of eighty, and sometimes to one hundred feet. It runs up straight for forty or fifty feet without a branch. Its top is spreading, and is ornamented with a thick and glossy foliage. The gum is collected by chopping through the bark with a hatchet and placing under each series of cuts a little clay cup formed by the hands of the workman. About a gill of the sap acc.u.mulates in each cup in the course of a day, and it is then transferred to receiving vessels and taken to camp. The first use of the gum was made by the South American Indians, who made shoes, bottles, playing b.a.l.l.s and various other articles from it. Their method for making a shoe was to take a crude wooden last, which they covered with clay to prevent the adhesion of the gum. It was then dipped in the sap, or the latter was poured over it, which gave it a thin coating. It was then held over a smoky fire, which gave it a dark color and dried the gum. When one coating became sufficiently hard another was added, and smoked in turn, and so successive coatings were applied until a sufficient thickness was obtained. When the work was completed it was exposed for some days in the sun, and while still soft the shoes were decorated as the fancy or taste of the maker suggested. The clay forms were then broken out, and the shoe stuffed with gra.s.s to keep it in shape for use or sale. In 1820 a pair of these clumsy shoes was brought to Boston and exhibited as a curiosity. They were covered with gilding, and resembled the shoe of a Chinaman. Subsequently considerable numbers of these shoes were brought from South America, and being sold at a large price, they served to stimulate Yankee ingenuity into devising methods of making them from the raw material, which being brought as ballast in the ships from Brazil, could be had cheaply. In France some attention had been given to the material, and the rubber bottles of the Indians had been cut into narrow threads which were woven into strips of cloth to form suspenders and garters. In England an application of it in thin solution had been made by a Mr. Macintosh, who spread it between two thicknesses of thin cloth to form Macintosh water-proof coats. The first practical use of the gum on a large scale was inst.i.tuted by Mr. Chaffee in Roxbury, Ma.s.s., about 1830. He dissolved the gum in spirits of turpentine and invented steam-heated rolls for spreading it upon cloth. Companies were formed to exploit the products, and in the fall and winter of 1833 and 1834 many thousands of dollars' worth of goods were made by the Roxbury Company, but the business proved a total failure, for in the summer the goods melted, decomposed and became so offensive as to be worse than useless, while the cold of winter rendered them stiff and liable to crack. With a knowledge of these facts and conditions Charles Goodyear commenced his experiments, believing that there was a great future for this material if it could only be prevented from melting in summer and stiffening in winter. He tried mixing it with many materials, first using magnesia, which, however, proved ineffective. On June 17, 1837, he took out patent No. 240, in which he proposed to destroy the adhesive properties of caoutchouc by superficial application of an acid solution of the metals, nitric acid with copper or bis.m.u.th being specially recommended. He also claimed the incorporation of lime with the gum to bleach it. Under this process Mr. Goodyear made various articles in the form of fabrics, toys and ornamental articles, using the fabric to make clothing for himself, which he wore to demonstrate its value and wearing qualities. A striking word picture of Mr. Goodyear at this time is given by the reply of a gentleman who, being asked by a man looking for Mr. Goodyear as to how he might recognize him, replied, "If you meet a man who has on an India rubber cap, stock, coat, vest, and shoes, and an India rubber money purse in his pocket, without a cent of money in it, that is he."

Many useful and artistic articles were made under this first patented process, including maps, surgical bandages, etc., and were brought by Mr. Goodyear to the notice of President Jackson, Henry Clay and John C.

Calhoun, from whom he received very encouraging letters. His efforts, however, to introduce his process commercially were not attended with success. Capitalists and manufacturers had been rendered so conservative by the large loss of money in the Roxbury Company, that they were disinclined to have anything further to do with it. Practically alone he was obliged to continue his work. By the kindness of Mr. Chaffee and Mr.

Haskins he was allowed the use of the valuable machinery standing idle in their factory at Roxbury, and he made shoes, piano covers, table cloths and carriage covers of superior quality, and from the sale of these, and of licenses to manufacture, he for the first time was able to support his family in comfort. Mr. Goodyear had not yet discovered, however, the process of vulcanization, upon which the rubber industry is founded. In 1838 Mr. Nathaniel Hayward, of Woburn, Ma.s.s., who had been employed in the bankrupt rubber company, discovered that the stickiness of the rubber could be prevented by spreading a small quant.i.ty of sulphur on it. The same result had also been noticed by a German chemist. On Feb. 24, 1839, Mr. Hayward procured the patent, No. 1,090, on his process, and a.s.signed it to Mr. Goodyear. The patent covered a process of dissolving sulphur in oil of turpentine and mixing it with the gum, and also included the incorporation of the dry flowers of sulphur with the gum, the product afterwards being treated by Mr.

Goodyear's metallic salt process. This was the starting point of vulcanization, for vulcanization consists simply in admixing sulphur with the rubber, and then subjecting it for six to eight hours to a temperature of about 300. Its effect is to so change the nature of the gum to prevent it from melting or becoming sticky under the influence of heat, or of hardening and becoming stiff under the influence of cold, the vulcanized gum remaining elastic, impervious, and unchangeable under all ordinary conditions. This great discovery of the influence of heat on the sulphur treated gum was quite accidental and wholly unexpected.

Heat above all things was the agency which in all previous observations was most to be feared, for it was this more than anything else that melted down, decomposed and destroyed all of his manufactured articles.

While sitting near a hot stove engaged in an animated discussion concerning his experiments, a piece of the gum treated with sulphur, which he held in his hand, was, by a rapid gesture, thrown upon the stove. To his astonishment, he found that this relatively high heat did not melt it, as heretofore, and while it charred slightly, it was not made at all sticky. He nailed the piece of gum outside the kitchen door in the intense cold, and upon examining it the next morning found it as perfectly flexible as when he put it out. Goodyear had discovered the process which afterwards came to be known as "vulcanization." The discovery was made in 1839, but was not accepted by those to whom it was submitted as possessing any importance. Prof. Silliman, of Yale College, however, in the fall of 1839 testified to the results claimed for it by Mr. Goodyear--that it did not melt with heat, nor stiffen with the cold.

On June 15, 1844, Mr. Goodyear took out his celebrated patent, No.

3,633, covering this process, in which he not only used sulphur, but added a proportion of white lead. The proportions named were 25 parts of rubber, 5 parts of sulphur, and 7 parts of white lead, the ingredients either to be ground in spirits of turpentine, or to be incorporated dry between rolls. The odor imparted by the sulphur was to be destroyed by washing with potash or vinegar. This patent was reissued in two divisions Dec. 25, 1849, and again on Nov. 20, 1860, and was extended for seven years from June 15, 1858, which was the end of the first term.

Under this patent two kinds of rubber were made and sold--"soft rubber,"

containing only a small proportion of sulphur, while the other, known as the "vulcanite," "ebonite," or "hard rubber," had from 25 to 35 per cent. of sulphur and was subjected to a longer heat.

The history of this patent is a remarkable one. Immensely valuable as it was, Goodyear reaped but a small share of the profit, for in the midst of his poverty and necessities he was obliged to sell licenses and establish royalties at a figure far below the real value of the rights conveyed. Some idea of the great value of the business which Mr.

Goodyear had developed may be had from the fact that the companies who held rights under the patent for the manufacture of shoes paid at one time to Daniel Webster the enormous fee of $25,000 for defending their patent interests.

With the idea of extending his invention Mr. Goodyear visited England in 1851, where he found that Thomas Hanc.o.c.k, of the house of Macintosh & Co., had forestalled him, although not the inventor. A peculiar provision of the English patent law, which gives the patent to the first introducer, permitted this. Nothing daunted, however, he organized a magnificent exhibit for the Great International Exhibition held in Crystal Palace at Hyde Park, London, in 1851. This exhibit cost him $30,000, and he called it the Goodyear Vulcanite Court. It comprehended an elegantly constructed suite of open rooms made of hard rubber ornamented with handsome carvings, and furnished with rubber furniture, musical instruments, and globes made of rubber, and it was also carpeted with the same material. For his exhibit he received the "Grand Council Medal," which was one of the highest testimonials of the exposition.

This exhibit was afterwards moved from London to Sydenham, where it was exposed and used as an agency for some years for the sale of rubber goods.

[Ill.u.s.tration: FIG. 161.--MACHINE FOR GRINDING AND WASHING CRUDE RUBBER.]

Mr. Goodyear had obtained a French patent for his invention, and at the Exposition Universelle in Paris, in 1855, he fitted up at an expense of $50,000 two elegant courts with India rubber furniture, caskets and rich jewelry, and for this exhibit he had conferred upon him by the Emperor Napoleon the "Grand Medal of Honor" and the "Cross of the Legion of Honor." It was a singular instance of the irony of fate that the decoration of the "Cross of the Legion of Honor" should have been conveyed to him while imprisoned for debt in "Clichy," the debtors'

prison in Paris. The lofty courage of the man was well ill.u.s.trated at this time in his reply to his wife's solicitous inquiries as to how he had spent the night while in prison. He said, "I have been through nearly every form of trial that human flesh is heir to, and I find that _there is nothing in life to fear but sin_." The declining years of his life were full of sorrow, pain and affliction, and at his death in 1860 his estate was $200,000 in debt. He lived long enough, however, to see his material applied to nearly five hundred uses, giving employment in England, France and Germany to 60,000 persons, and producing in this country alone goods worth $8,000,000 a year.

[Ill.u.s.tration: FIG. 162.--MAKING RUBBER CLOTH.]

The greatest of all applications of rubber are to be found in the manufacture of boots and shoes. The number of attacks of cold, rheumatism, and death-dealing diseases from wet feet, that have been averted by the use of rubber shoes, can never be estimated, but perhaps it is safe to say that the rubber shoe has done more to conserve the health of the human family than any other single article of apparel.

In the manufacture of shoes the finest quality of rubber is received in wooden boxes 4 2 1 feet, containing about 350 pounds in lumps of 1 to 75 pounds. These lumps are cut to suitable size, and are then ground and washed in the machine shown in Fig. 161, water and steam being sprayed on the rubber during the operation. It is then worked into sheets or mats between rolls. From the grinding room the sheets are taken to the mixing room, where lampblack, sulphur and other ingredients are added, and worked into it by being pa.s.sed many times between heated rolls, the sheets being finally reduced to a thickness of less than 1/32 of an inch. The rubber sheets are then applied to a cloth backing by cloth calendering rolls, shown in Fig. 162, which are steam heated and by great pressure serve to incorporate the sheets of rubber and cloth into intimate and inseparable union. Out of this rubber fabric, which is made of different thicknesses for the upper, sole and heel, the patterns for the shoe are cut, and the parts are deftly fitted around the forms by girls, and secured by rubber cement, as shown in Fig. 163. The shoes are then covered with a coat of rubber varnish, and are put into cars and run into the vulcanizing ovens, where they remain from six to seven hours at a temperature of about 275. The goods are then taken out, and after being inspected are boxed for the market. The vulcanizing is a very important part of the manufacture of a rubber shoe, for it is absolutely necessary in order to give them stability and wearing qualities. A shoe that had not been vulcanized would mash down, spread, become sticky and go to pieces after a few hours' wear.

The rubber shoe industry of the United States is carried on by about fifteen large companies, representing an investment of many millions of dollars, most of which companies are located in Ma.s.sachusetts, Rhode Island and Connecticut.

Some idea of the immensity of this industry may be obtained from the import statistics. In 1899 the United States alone imported crude rubber to the extent of 51,063,066 pounds, as much as 1,000,000 pounds a month coming from the single port of Para. The export of manufactured rubber goods for the same year amounted to $1,765,385. The statistics for Great Britain for 1896 showed the imports of rubber to that country to be one-third more than the imports of the United States. Germany also is a large consumer. The great Harburg-Vienna factories cover sixty-seven acres, are capitalized at 9,000,000 marks, and employ 3,500 hands. Much fine technical apparatus, toys, and b.a.l.l.s are made here, the daily output of b.a.l.l.s reaching 8,000. These, with the Noah's arks of India rubber animals, are the delight of the little ones all over the world.

Although so much in evidence about us, India rubber is not by any means a cheap material. Costing only five cents a pound when Goodyear commenced his experiments, it is now worth a dollar a pound, and is therefore much more expensive than any of the ordinary metals, woods, or building materials. Many subst.i.tutes in the form of compositions of various ingredients have been devised and patented, but no real subst.i.tute for nature's product has yet been found. For many years old and worn out rubber goods were thrown away as worthless. Now all such rubber is reclaimed, and used in many grades of goods which do not require a pure gum. Insatiable as the demands of the trade may appear, there is no need to fear a rubber famine, for the forests of trees in South America and the East Indies are practically inexhaustible, and in the rich alluvial soil of their habitat nature's processes of growth rapidly restore the decimation.

[Ill.u.s.tration: FIG. 163.--MAKING RUBBER SHOES.]

Since the time of Goodyear, the amplification of this art and the multiplication of uses for rubber, and its increased commercial importance, have gone on at such a rate of increase that to-day we may be said to be living in the rubber age. Its uses and applications are legion, and they extend literally from the cradle to the grave. When the baby comes into the world its introduction to India rubber begins at once with the nursing bottle and the gum cloth, and when the aged invalid takes leave of the world his last moments are soothed with the water bag and the rubber bed, and between these extremes we find it in evidence everywhere about us. In wearing apparel it extends from the crown of the head to the sole of the foot--rubber cap, coat, gloves, and shoes. The man has it in his suspenders and his pipe stem, the woman in her garters and dress shields, and the baby in its teething ring and rattle. The soldier stands on picket duty in the rain, and the rubber blanket protects him from rheumatism. If wounded, the surgeon dresses his mangled limb with rubber bandages, and when he gets well he has a rubber cushion on the end of his crutch, or on the foot of his artificial leg. If wounded in the mouth perhaps the government gives him a set of artificial teeth on a rubber plate. The rubber mat greets you at the front door, a little pad cushions the door stops and the backs of chairs, and a ring seals the mouth of the fruit jar. The whole array of toilet articles, including combs, brushes, mirrors, shoe horns, etc., are made from it. In the parlor it is found in picture frames and the piano cover; in the bath room the wash rag, water bag, rubber cup, and hose pipe of the shower bath are all made of it; in the play room are found rubber b.a.l.l.s and toys of all kinds; in the kitchen the clothes wringer and the table cloth; in the dining room the handles of knives, and the tea tray, and what is more useful and more ubiquitous in the office than the rubber band, the rubber ruler, the pencil eraser, or the fountain pen? But these are only a few of the personal and indoor uses and applications. Rubber belting for machinery, fire engine and garden hose, steam engine packing, car springs, covers for carriages and the big guns of the navy, life preservers, billiard table cushions, and chemical and surgical apparatus in endless variety. The electrical world is almost entirely dependent upon it for the insulation of our ocean cables and electric light wires, for battery cups, and the insulating mountings of all electrical apparatus. The pneumatic bicycle tire could not exist without rubber, and the modern application of it to this use alone amounts to nearly four million pounds annually. Every automobile carriage takes twenty-five pounds of rubber for each tire, or 100 pounds altogether. This great and growing industry, together with the now common use of rubber tires on horse-drawn vehicles, raises the sum total of rubber employed in the arts to an enormous figure.

That the sap of an uncultivated tree in a swampy, tropical, and malarial forest, thousands of miles from civilization, should cut so great a figure in the necessities of modern life, seems strange and unaccountable on any basis of probabilities. It is only another ill.u.s.tration of the possibilities of the patient and persistent work of the inventor. Charles Goodyear took this nearly worthless material, and made of it, as Parton said in 1865--"not a new material merely, but a new cla.s.s of materials, applicable to a thousand divers uses. It was still India rubber, but its surface would not adhere, nor would it harden at any degree of cold, nor soften at any degree of heat. It was a cloth impervious to water; it was a paper that would not tear; it was a parchment that would not crease; it was leather which neither rain nor sun would injure; it was ebony that could be run into a mould; it was ivory that could be worked like wax; it was wood that never cracked, shrunk nor decayed. It was metal, 'elastic metal,' as Daniel Webster termed it, that could be wound round the finger, or tied into a knot, and which preserved its elasticity like steel. Trifling variations in the ingredients, in the proportion and in the heating, made it either pliable as kid, tougher than ox hide, as elastic as whalebone, or as rigid as flint."

CHAPTER XVIII.

CHEMISTRY.

ITS EVOLUTION AS A SCIENCE--THE COAL TAR PRODUCTS--FERMENTING AND BREWING--GLUCOSE, GUN COTTON AND NITRO-GLYCERINE--ELECTRO-CHEMISTRY --FERTILIZERS AND COMMERCIAL PRODUCTS--NEW ELEMENTS OF THE NINETEENTH CENTURY.

The foundation stones of empirical discovery, upon which this science is based, had been crudely shaped by the workmen of preceding centuries, but the cla.s.sification and laying of them into the structure of an exact science is the work of the Nineteenth Century. The gla.s.s of the Phnicians, and the dyes and metallurgical operations of the Egyptians, involved some chemical knowledge; much more did the operations of the alchemists, who vainly sought to convert the baser metals into gold, but these were only the crude building stones, out of which the great complex modern structure has been raised. In the Sixteenth Century the study of chemistry, apart from alchemy, began, and some attention was given to its application to the uses of medicine. Aristotle's four elements--fire, air, earth and water--were no longer accepted as representing a correct theory, and new ones were proposed only to be found as erroneous, and to be superseded in time by others.

Briefly traversing the more important of the earlier steps, there may be mentioned the phlogiston theory of Stahl in the earlier part of the Eighteenth Century; the discovery of the composition of water by Cavendish in 1766; of oxygen by Priestly and Scheele in 1774; the electro-chemical dualistic theory of Lavoisier in the latter part of the Eighteenth Century, followed by a rational nomenclature established by Guyton de Morveau, Berthollet and Fourcroy; the doctrine of chemical equivalents by Wenzel in 1777 and Richter in 1792; Dalton's atomic theory; Wollaston's scale of chemical equivalents; Gay Lussac's law of combining volumes; Berzelius' system of chemical symbols and theory of compound radicals; contributions of Sir Humphrey Davy and Faraday in electro-chemistry, and Thenard's grouping of the metals. These interesting phases of development of the old chemistry have been followed by the new theory of subst.i.tution, by Dumas and others. This change, beginning about 1860 and running through a period of nearly twenty years, has gradually supplanted the old electro-chemical dualistic theory and established the present system.

Among the important and interesting achievements of chemistry in the Nineteenth Century is the _artificial production of organic compounds_.

All such compounds had heretofore been either directly or indirectly derived from plants or animals. In 1828 Wohler produced urea from inorganic substances, which was the first example of the synthetic production of organic compounds, and it was for many years the only product so formed. Berthelot, of Paris, by heating carbonic oxide with hydrate of potash produced formiate of potash, from which formic acid is obtained; by agitating olefiant gas with oil of vitriol a compound is produced from which, upon the addition of water and distillation, alcohol is formed; he also re-combined the fatty acids with glycerine to form the original fats.

In the cla.s.sification of this science, it has been divided into inorganic chemistry, relating to metals, minerals and bodies not a.s.sociated with organic life, and organic chemistry, which was formerly limited to matter a.s.sociated with or the result of growth or life processes, but which is now extended to the broader field of all carbon compounds. In later years the most remarkable advances have been made in the field of organic chemistry. The four elements carbon, hydrogen, oxygen and nitrogen have been juggled into innumerable a.s.sociations, and in various proportions, and endless permutations, have been combined to produce an unlimited series of useful compounds, such as dyes, explosives, medicines, perfumes, flavoring extracts, disinfectants, etc.

The most interesting of these compounds are the _coal tar products_.

Coal tar, for many years, was the waste product of gas making. Forty years ago about the only use made of it was by the farmer, who painted the ends of his fence posts with it to prevent decay, or by the fisherman, who applied it to the bottoms of his boats and his fishing nets. To-day the black, offensive and unpromising substance, with magical metamorphosis, has been transformed by the chemist into the most beautiful dyes, excelling the hues and shades of the rainbow, the most delightful perfumes and flavoring extracts, the most useful medicines, the most powerful antiseptics, and a product which is the very sweetest substance known. The aniline dyes represent one of the great developments in this field. In 1826 Unverdorben obtained from indigo a substance which he called "Crystalline." In 1834 Runge obtained from coal tar "Kyanol." In 1840 Fritzsch obtained from indigo a product which he called "Aniline," from "Anil," the Portuguese for indigo. Zinin soon after obtained "Benzidam." All these substances were afterward proved to be the same as aniline. Perkins' British patent, No. 1,984, of 1856, is the first patented disclosure of the aniline dyes, and represents the beginning of their commercial production. This combines sulphate of aniline and bichromate of potash to produce an exquisite lilac, or purple color. The first United States patent was in 1861, and now there are about 1,400 patents on carbon dyes and compounds, the most of which belong to the coal tar group. In dyes artificial alizarine, by Graebe and Lieberman (Pat. No. 95,465, Oct. 5, 1869); aniline black, by Lightfoot (Pat. No. 38,589, May 19, 1863); naphthazarin black, by Bohn (Pat. No. 379,150, March 6, 1888); artificial indigo, by Baeyer (Pat.

No. 259,629, June 13, 1882); the azo-colors, by Roussin (Pat. No.

210,054, Nov. 19, 1878); and the processes for making colors on fibre, by Holliday (Pat. No. 241,661, May 17, 1881), are the most important.

The artificial production of salicylic acid, by Kolbe (Pat. No. 150,867, May 12, 1874), marks an important step in antiseptics. Artificial vanilla, by Fritz Ach (Pat. No. 487,204, Nov. 29, 1892), represents flavoring extracts; and artificial musk, by Baur (Pat. No. 536,324, March 26, 1895), is an example of perfumes. In medicines a great array of compounds has been produced, such as antipyrin, the fever remedy, by Knorr (Pat. No. 307,399, Oct. 28, 1884); phenacetin, by Hinsberg (Pat.

No. 400,086, March 26, 1889); salol, by Von Nencki (Pat. No. 350,012, Sept. 28, 1886), and sulfonal by Bauman (Pat. No. 396,526, Jan. 22, 1889). To these may be added antikamnia (acetanilide), the headache remedy, and saccharin, by Fahlberg (Pat. No. 319,082, June 2, 1885), which latter is a subst.i.tute for sugar, and thirteen times sweeter than sugar. Among the more familiar products of coal tar or petroleum are moth b.a.l.l.s, carbolic acid, benzine, vaseline, and paraffine.

In the commercial application of chemistry the work of Louis Pasteur in _fermenting_ and _brewing_ deserves special notice as making a great advance in this art. His United States patent, No. 141,072, July 22, 1873, deals with the manufacture of yeast for brewing.

The manufacture of _sugar_ and _glucose_ from starch is an industry of great magnitude, which has grown up in the last twenty-five years.

Water, acidulated with 1/100th part of sulphuric acid, is heated to boiling, and a hot mixture of starch and water is allowed to flow into it gradually. After boiling a half hour chalk is added to neutralize the sulphuric acid, and when the sulphate of lime settles the clear syrup is drawn off, and either sold as syrup, or is evaporated to produce crystallized grape sugar, which latter is only about half as sweet as cane sugar. Glucose syrup, however, has largely superseded all other table syrups, and is extensively used in brewing, for cheap candies, and for bee food. Our exports of glucose and grape sugar for 1899 amounted to 229,003,571 pounds, worth $3,624,890.

An important discovery, made in 1846, was that carbohydrates, such as starch, sugar, or cellulose, and glycerine, when acted upon by the strongest nitric acid, produced compounds remarkable for their explosive character. _Gun cotton and nitro-glycerine_ are the most conspicuous examples. Gun cotton is made by treating raw cotton with nitric acid, to which a proportion of sulphuric acid is added to maintain the strength of the nitric acid and effect a more perfect conversion. Besides its use as an explosive, gun cotton when dissolved in ether has found an important application as collodion in the art of photography.

Nitro-glycerine only differs in its manufacture from gun cotton in that glycerine is acted upon by the acids, instead of cotton. Pyroxiline, xyloidine, and celluloid are allied products, which have found endless applications in toilet articles and for other uses, as a subst.i.tute for hard rubber.

The applications of chemistry in the commercial world have been in recent years so numerous and varied that it is not possible to do more than to refer to its uses in the manufacture of soda and potash, of alcohol, ether, chloroform, and ammonia, in soap making, washing compounds and tanning, the production of gelatine, the refining of cotton seed and other oils, the art of oxidizing oils for the manufacture of linoleum and oil cloth, the manufacture of fertilizers, white lead and other paints, the preparation of proprietary medicines, of soda water and photographic chemicals, the manufacture of salt and preserving compounds, in the fermentation of liquors and brewing of beer, the preparation of cements and street pavements, the manufacture of gas, and the embalming of the dead.

The most interesting and, in many respects, the most important, development of the last twenty-five years has been in _electro-chemistry_. Electro-chemical methods are now employed for the production of a large number of elements, such as the alkali and alkaline earth metals, copper, zinc, aluminum, chromium, manganese, the halogens, phosphorus, hydrogen, oxygen, and ozone; various chemicals, including the mineral acids, hydrates, chlorates, hypochlorites, chromates, permanganates, disinfectants, alkaloids, coal tar dyes, and various carbon compounds; white lead and other pigments; varnish; in bleaching, dyeing, tanning; in extracting grease from wool; in purifying water, sewerage, sugar solutions, and alcoholic beverages. The present low price of _aluminum_, reduced from $12 per pound in 1878 to 33 cents now, is due to its production by electrical methods. Among the earliest successful processes is that described in patents to Cowles and Cowles, No. 319,795, June 9, 1885, and No. 324,658, August 18, 1885, in which a mixture of alumina, carbon and copper is heated to incandescence by the pa.s.sage of a current, the reduced aluminum alloying with the copper. This has now been superseded by the Hall process (Pat. No.

400,766, April 2, 1889), in which alumina, dissolved in fused cryolite, is electrolytically decomposed. Practically all the copper now produced, except that from Lake Superior, is refined electrolytically by substantially the method of Farmer's patent (Pat. No. 322,170, July 14, 1885). All metallic sodium and pota.s.sium are now obtained by electrolysis of fused hydroxides or chlorides (Pats. No. 452,030, May 12, 1891, to Castner, and No. 541,465, June 25, 1895, to Vautin). The production of caustic soda, sodium carbonate, and chlorine by the electrolysis of brine, is carried on upon a large scale, and will probably supersede all other methods. Nolf's process (Pat. No. 271,906, Feb. 6, 1883), and Caster's (No. 528,322, Oct. 30, 1894), employ a receiving body or cathode of mercury, alternately brought in contact with the brine undergoing decomposition, and with water to oxidize the contained sodium. _Carborundum_, or silicide of carbon, is largely superseding emery and diamond dust as an abradant. It is produced by Acheson (Pat. No. 492,767, Feb. 28, 1893), by pa.s.sing a current of electricity through a mixture of silica and carbon. _Calcium carbide_, a rare compound a few years ago, is now cheaply produced by the action of an electric arc on a mixture of lime and carbon, as described by Willson (Pats. Nos. 541,137, 541,138, June 18, 1895). Calcium carbide resembles c.o.ke in general appearance, and it is used for the manufacture of acetylene gas, for which purpose it is only necessary to immerse the calcium carbide in water, and the gas is at once given off by the mutual decomposition of the water and the carbide.