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 classification and laying of them into the structure of an exact
science is the work of the Nineteenth Century. The glass of the
Phœnicians, 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found as erroneous, and to be superseded in time by others.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 substitution, 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 classification of this science, it has been divided into
inorganic chemistry, relating to metals, minerals and bodies not
associated with organic life, and organic chemistry, which was formerly
limited to matter associated 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 associations, 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 substitute for sugar, and thirteen times sweeter than
sugar. Among the more familiar products of coal tar or petroleum are
moth balls, 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 substitute 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 passage 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 potassium 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 passing 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
coke 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.
_Agricultural chemistry_ is another one of the practical developments of
the Nineteenth Century. A hundred years ago the farmer planted his
crops, prayed for rain, and trusted to Providence for the increase; he
was not infrequently disappointed, but was wholly unable to account for
the failure. To-day the intelligent farmer understands the value of
nitrogen, has ascertained how it may be fed to his crops through the
agency of nitrifying organisms, or he has his soil analyzed at the
Agricultural Department, finds out what element it lacks for the crop
desired, and in chemically prepared fertilizers supplies that
deficiency. The chemical analysis of drinking water has also
contributed much to the knowledge of right living and to the avoidance
of disease and death, which our forefathers were accustomed to regard as
dispensations of Providence.
America has furnished some eminent chemists in the Nineteenth Century,
who have made valuable contributions to the science, notably in the
field of metallurgy. It is a fact, however, which must be admitted with
regret, that America has not in the field of chemical research occupied
the leading place she has in mechanical progress. The European
laboratory is the birthplace of most modern inventions in the chemical
field, and this is so simply by reason of the fact that these more
patient investigators have set themselves studiously, systematically and
persistently to the work of chemical invention. It is said that some of
the large commercial works in Germany have over 100 Ph. D.’s in a single
manufacturing establishment, whose work is not directed to the
management of the manufacture, but solely to original research, and the
making of inventions. The laboratories in such works differ from those
in the universities only in being more perfectly equipped, and more
sumptuously appointed. The result of this is seen in the fact that in
1899 the United States imported coal tar dyes alone to the extent of
$3,799,353, and 5,227,098 pounds of alizarine, most of which came from
Germany, and for which we paid a good price, since the German
manufacturers control the United States patents. The alizarine dyes are
for the most part the artificial kind made by German chemists. Prior to
1869 the red alizarine dye was of plant origin, being obtained from
madder root, and it cost $2 a pound. The German chemist produced an
artificially made product, which took the place of the madder dye, and
was sold at $1.20 a pound. At the end of the patent term (seventeen
years) the price fell to 15c. a pound, showing that the product was
produced at a profit of more than $1.05 a pound, and as millions of
pounds were imported annually, it is estimated that $35,000,000 was the
price paid the German chemists for their foresight in combining science
with business. Many United States patents granted to foreign chemists
are still in force, and the rich reward of their skill is reaped at our
expense.
_Discovery of elements._--In the early days of chemical knowledge, fire,
air, earth and water constituted the insignificant category of the
elements, which was as faulty in classification as it was small in size.
Gradual splitting up of compounds, and an increase in the number of
elements, has gone on progressively for some hundreds of years, until
to-day the list extends well on to one hundred elementary bodies. Those
which belong to the credit of the Nineteenth Century are given in the
table following, with the name of the discoverer, and the date of its
discovery.
ELEMENTS DISCOVERED IN THE NINETEENTH CENTURY.
ELEMENTS. DISCOVERER. YEAR.
Columbium Hatchett 1801
Tantalum Ekeberg 1802
Iridium Tenant 1803
Osmium Tenant 1803
Cerium Berzelius 1803
Palladium Wollaston 1804
Rhodium Wollaston 1804
Potassium Davy 1807
Sodium Davy 1807
Barium Davy 1808
Strontium Davy 1808
Calcium Davy 1808
Boron Davy 1808
Iodine Courtois 1811
Cyanogen Gay Lussac 1814
(Comp. rad.)
Selenium Berzelius 1817
Cadmium Stromeyer 1817
Lithium Arfvedson 1817
Silicon Berzelius 1823
Zirconium Berzelius 1824
Bromine Balard 1826
Thorium Berzelius 1828
Yttrium Wohler 1828
Glucinum Wohler 1828
Aluminum Wohler 1828
Magnesium Bussey 1829
Vanadium Sefstroem 1830
Lanthanum Mosander 1839
Didymium Mosander 1839
Erbium Mosander 1843
Terbium Mosander 1843
Ruthenium Claus 1845
Rubidium Bunsen 1860
Caesium Bunsen 1860
Thallium Crookes 1862
Indium {Reich } 1863
{Richter}
Gallium Boisbaudran 1875
Ytterbium Marignac 1878
Samarium Boisbaudran 1879
Scandium Nilson 1879
Thulium Cleve 1879
Neodymium Welsbach 1885
Praseodymium Welsbach 1885
Gadolinium Marignac 1886
Germanium Winkler 1886
Argon {Raleigh} 1894
{Ramsey }
Krypton { Ramsey } 1897
{ Travers }
Neon {Ramsey } 1898
{Travers}
Metargon { Ramsey } 1898
{ Travers }
Coronium Nasini 1898
Xenon Ramsey 1898
Monium Crookes 1898
Etherion (?) Brush 1898
Whether or not these so-called elements are really true elementary forms
of matter, which are absolutely indivisible, is a problem for the
chemists of the coming centuries to solve. The classification has the
approval of the present age. What new elements may be found no one may
predict. Mendelejeff’s _periodic law_, however, suggests great
possibilities in this field. Allotropism, in which the same element will
present entirely different physical aspects, is also a significant and
suggestive phenomenon, for in it we see carbon appearing at one time as
a crude, black and ungainly mass of coal, and at another it appears as
the limpid and flashing diamond. In more than one mind there is a
lurking suspicion that there may, after all, be only one form of
primordial matter, from which all others are derived by some wondrous
play of the atoms, and if so the old idea of the alchemist as to the
transmutation of metals may not be entirely wrong. The Twentieth Century
may give us more light.