The Progress of the Century - Unknown

LiCl	BeCl₃	BCl₃	CCl₄	NH₄Cl
Na₂O	MgO	B₂O₃	SiO₂	PCl₃
Monad.	Dyad.	Triad.	Tetrad.	Triad and Pentad.
OH₂		FH		Ne——
SO₃		Cl(OH)O₃		A——
Dyad and Hexad.		Monad and Heptad.		No valency.

The elements of no valency are of recent discovery. In 1894 Lord Rayleigh had determined the density of the nitrogen of the atmosphere, having separated from it the oxygen and carbon dioxide which is mixed with nitrogen in air. He found it to be of somewhat higher density than that obtainable from ammonia and other compounds of nitrogen. In conjunction with Ramsay he investigated atmospheric nitrogen; it was absorbed either by a method devised by Cavendish, or by making it combine with magnesium at a red heat. They found that the unabsorbable residue possessed an unknown spectrum, and that its density was nearly 20. To this new gas they gave the name “argon,” or inactive, seeing that all attempts to cause it to enter into combination had failed. In 1895 Ramsay, searching for possible combinations of argon in minerals, experimented with one which had been previously examined by Hillebrand, of Baltimore, and obtained from it helium, a gas of density 2, possessing a spectrum which had been previously discovered in 1868 in the chromosphere of the sun, by Jannsen, of Paris, and named helium by Frankland and Lockyer. Subsequent liquefaction of crude argon by means of liquid air, prepared by a process invented simultaneously by Linde and Hampson, gave a residue which was named by its discoverers, Ramsay and Travers, “neon.” Liquid argon has yielded two other gases also, “krypon” and “xenon.” These elements form a separate group in the Periodic Table, commencing with helium, with atomic weight, 4; neon, 20; argon, 40; krypon, 82; and xenon, 128. They all agree in being mono-atomic, i.e., their molecules consist of single atoms; and they have no tendency to form compounds, i.e., they possess no valency.

In this sketch of the progress of chemistry during the century which has just passed, attention has been paid chiefly to the progress of thought. Allusions must, however, be made to the applications of chemistry to industrial purposes. The development of the soda industry, the preparation of carbonate of soda and caustic from common salt—initiated in France by LeBlanc (1742–1806)—has been developed by Tennant, in Scotland, and Muspeath and Gossage, and by Hargreaves, Weldon, and Maetea, in England; this process has at present a serious rival in the ammonia-soda process, developed by Solway, in Belgium, and by Brunner and Mond, in England. The main action of sulphuric acid, so long associated with the alkali process, has made enormous strides during the present century, but is still, in the main, the original process of causing sulphur dioxide in presence of water to absorb the oxygen of the air through nitric oxide. But the saving of the oxides of nitrogen through the invention of a sulphuric acid power by Gay-Lussac, known by his name, and the re-utilization of these oxides in the “Glover” power, invented by John Glover, of Newcastle, have greatly lessened the cost of the acid. Concentration of the acid in iron vessels is now common, the cost of platinum or of fragile glass vessels being thereby saved. The desulphurization of iron and the removal of silicon, carbon, and phosphorus by Bessemer’s process, modified by Thomas and Gilchrist through the introduction of a “basic magnesia lining” for the convertors, has made it possible to obtain pure iron and steel from ores previously regarded as of little value.

The use of artificial manures, prepared by mixing refuse animal matters with tetra-hydrogen, calcium phosphate, and nitrate of soda, or sulphate of ammonia, first introduced by Liebig, has created a revolution in agricultural methods and in the weight of crops obtainable from a given area of soil. The influence of manures on crops has been fully studied by Lawes and Gilbert for more than fifty years in their experimental farm at Rothampstead. The most remarkable advances which have been made, however, are due to cheap electric current. The electrolysis of alumina, dissolved in fused cryolite to obtain aluminum, an operation carried out at Schaffhausen-on-the-Rhine, and at the Falls of Foyers, in Scotland; the electro-deposition of pure copper for electric wires and cables, electro-silvering, gilding, and nickelling, all these are instances where decomposition of a compound by the electric current has led to important industrial results. At present soda and chlorine are being manufactured by the electrolysis of salt solution contained in rocking trays, one of the electrodes being mercury, by the Castner-Kellner process. This manufacture is being carried on at Niagara, as well as in England. But electricity as a heating agent finds ever-extending application. Louis Moisson, professor at Paris, led the way by utilizing the enormous heat of the ore in his electric furnace, thereby, among other interesting reactions, manufacturing diamonds, small, it is true, though none the less real. The use of electricity as a heating agent has received new applications. Phosphorus is now made by distilling a mixture of phosphates of lime and alumina with coke; a new polishing agent has been found in “carborundum,” a compound of carbon and silicon, produced by heating in an electric furnace a mixture of sand and coke; and cyanide of potassium, almost indispensable for the extraction of gold from ores poor in gold, is now manufactured by heating a mixture of carbon and carbonate of barium in an electric furnace in a current of carbon monoxide. These are but some of the instances in which electricity has been adopted as an agent in effecting chemical changes; and it may be confidently predicted that the earlier years of the twentieth century will witness a great development in this direction. It may be pointed out that the later developments of industrial chemistry owe their success entirely to the growth of chemical theory; and it is obvious that that nation which possesses the most competent chemists, theoretical and practical, is destined to succeed in the competition with other nations for commercial supremacy and all its concomitant advantages.

William Ramsay.

ARCHÆOLOGY

To write of the progress of archæology in this century is scarcely possible, as the idea of the subject was unknown a hundred years ago; it is, therefore, the whole history of its opening and development that we have to deal with. The conception of the history of man being preserved to us in material facts, and not only in written words, was quite disregarded until the growth of geology had taught men to read nature for themselves, instead of trusting to the interpretations formed by their ancestors. Even down to the present the academic view is that classical archæology is more important than other branches, because it serves to illustrate classical literature. Looked at as archæology, it is, on the contrary, the least important branch, because we already know so much more of the classical ages than we do of others.

It is only within the present generation that it has been realized that wherever man has lived he has left the traces of his action, and that a systematic and observant study of those remains will interpret to us what his life was, what his abilities and tastes were, and the extent and nature of his mind. Literature is but one branch of the archæology of the higher races; another—equally important for the understanding of man—is art; these two give the highest and most complex and characteristic view of the nature of a race. At the opposite end of the scale are the rudest stone weapons which remain as the sole traces of the savages who used them. These highest and lowest evidences of mind, and all that lies between them, are the domain of archæology.