interest awakened of late in electricity, have given rise to numerous researches aiming at a representation of chemical reactions as mere transformations of heat-energy or electricity. And, finally, most skillful investigations are being made, and most suggestive hypotheses advanced as regards the possible distribution of atoms within the molecules, under the supposition of their remaining in a state of equilibrium; and thus the way is prepared for a higher conception of the atoms—not motionless and mutually equilibrated, but involved, like the planets of our solar system, in complicated movements within the molecules. Works of importance have appeared of late in each of these directions. But no other domain has lately been explored with such a feverish activity as the vast domain of solutions; and to these researches we must now turn our attention.
In former times it was supposed that if some table-salt or sugar (or any other solid, liquid, or gas) is dissolved in water or in any other liquid, the particles of the dissolved body will simply spread, or glide, between the particles of the solvent, and simply be mixed together—just as if we had made a mixture of two different powders or two gases. But on a closer study a succession of most complicated and unexpected phenomena was revealed, even in so simple a fact as the solution of a pinch of salt in a tumbler of water. The solutions proved to be the arena upon which phenomena cease to be purely physical, and become chemical, and they were studied accordingly with the hope that they might give a physical cue to chemical reactions. Hundreds of researches are contributed every year to this subject; and although there is yet no final result to record, we are bound nevertheless to examine the present state of investigations which so much interest and excite chemists.
- The committee appointed by the British Association for reporting on the bibliography of solutions had catalogued no less than 255 papers, which appeared in 1890, in a few periodicals only. The total was at that time 930 papers.
- We know no general review of this extremely complicated question which we might recommend to the general reader. The address delivered by Prof. Orme Masson before the Australasian Association for the Advancement of Science, in January, 1891; Prof. S. U. Pickering's Report to the British Association, in 1890, on the hydrate theory of solution, followed by a most interesting discussion between Profs. Gladstone, Arrhenius, Armstrong, Fitzgerald, Van 't Hoff, Lodge, Ostwald, and Ramsay, and the elaborate report, by W. N. Shaw, on electrolysis (British Association Reports, 1890, Leeds), are excellent sources of general information. Ostwald's work, Solutions (English translation in 1891), as well as his Lehrbuch der allgemeinen Chemie (Leipsic, 1885; new edition of first volume in 1892), and the review, Zeitschrift flir physikalische Chemie, which he publishes since 188V, unhappily take but little notice of the chemical aspects of the question. Mendeléeff's foot-notes in his most remarkable Principles of Chemistry (London, 1891) are perhaps, on the whole, the best means for gaining a general and impartial insight into the whole question. Though himself one of the earliest promoters of the hydrate or chemical theory of solutions, he