tals of remarkable size"; the liquefaction of air has been so conducted as to obtain two distinct liquids separated by a perfectly visible meniscus (Wroblewski); and, finally, when hydrogen was subjected to between 100 and 200 atmospheres pressure in small glass tubes surrounded by oxygen boiling in vacuo, it condensed to colorless drops.
These noteworthy results are triumphs of physics rather than of chemistry, but no review of chemical progress can afford to omit them; their bearing on the molecular theory of matter justifies the space given them. It seems probable, moreover, that every known substance on the face of the earth will be eventually obtained in solid form by the mere withdrawal of heat. At these low temperatures the chemical activity of bodies is greatly lessened or ceases, but additional observations must be made on this point before attempting generalizations.
Experiments of the character described demand great resources and are not devoid of danger; those conducting them will be rewarded by undying fame.
The progress of chemistry, in its more material aspects, is characterized by the improved and economic production of known substances, by the discovery and manufacture of entirely new ones, and by novel applications of both these classes as well as of waste materials. The necessity of utmost condensation precludes enumeration of even a centesimal part of the processes and products, nor would the mere catalogue be profitable. Omitting for the present the prolific department of organic chemistry, brief mention may be made of improvements in the metallurgy of nickel (now known to be malleable and ductile), of attempts to cheapen the production of aluminium, of the revival of the barium-dioxide process for manufacturing oxygen on a large scale, of novelties in artistic keramics, of the industrial production and application of the rare metal vanadium, of the successful introduction of water-gas as an illuminating agent, and of constant activity in the fascinating field of photography.
No chemical manufactures are more important than those grouped under the name "alkali industry," which comprises the production of those adjuncts of civilization, carbonate of soda, caustic soda, bicarbonate of soda, and bleaching-powder. Conducted by the methods originated by the ill-fated Nicolas Leblanc, they have, after a century's successful career, begun to give way to a youthful rival. The struggle to maintain the supremacy of Leblanc's process has been severe, the problem being a purely financial one. At first, the profits were made exclusively on the soda; then the decreasing profits, as well as the necessity of condensing the torrents of hydrochloric acid, led manufacturers to add to the production of alkali that of bleaching-powder, and the latter then yielded the profits, while the soda became a by-product. Sharp competition in England and France pushed prices below profitable production, and capitalists with millions in-
