THE POPULAR SCIENCE MONTHLY.
ful. Sir Henry Roscoe moved a vote of thanks to M. Moissan and M. Meslans. The vote, he said, must be regarded as coming from the whole Association and not simply from the Chemical Section. Prof. T. E. Thorpe seconded the motion, which was carried with loud cheers, and the president of the section. Dr. Emerson Reynolds, sent a telegram to M. Moissan congratulating him, on behalf of the section, on the great success of the demonstration.
Bacteriology in Chemistry.—Bacteriology, said Prof. Frankland, opening the discussion of that subject in the British Association, although originally an offshoot of botany, received its great impulse from the association with chemistry which began with the researches of Pasteur, while the greater part of our more recent knowledge was due to the labors of those medical men who had followed in the steps of Koch and his pupils. The progress that has been made of late years in this line of research was mainly due to the methods of producing pure and selective cultivations. These methods did not at present seem capable of any great modification, and a knowledge of them might be regarded as essential in a really liberal education. Pure cultivations of yeasts were now articles of commerce, and pure cultivations of microbes for purposes of research could be obtained in the same manner as pure chemicals. Bacteria, whose properties had been modified by successive cultivations, are also supplied in quantities for the preventive inoculation of cattle. Later work had shown that the differentiation of even the most carefully studied bacteria, such as those of cholera and typhoid, was very difficult, and the morphological characteristics which were originally employed almost exclusively had given way to chemical and pathogenic tests. Individuals of the same bacterium under different conditions will show greater variations than are shown by different species. The fermentations produced by bacteria, as distinct from those produced by yeasts, were of constantly increasing importance, and had afforded means of splitting up certain compounds and isolating new products that could not be obtained in any other way. The compounds fermentable in this way belonged to a very few chemical groups, and the products of the change were few in number and comparatively simple in character. It would seem that while the same compound might yield different products when acted upon by different organisms, one and the same organism would yield the same products even when it acted on substances of very different composition. By reason of their selective action and their tendency to attack certain compounds in preference to others in the same liquid, bacteria enabled us to separate substances of identical chemical composition but different physical properties which could not as yet be separated in any other way.
Arctic Rivers.—The rivers which flow into the Arctic Ocean, said Mr. Henry Seebohm in the British Association, are some of them among the greatest in the world. Some idea of the relative sizes of the drainage areas of a few of the best-known rivers may be learned from the following, in which the Thames, with a drainage area of 6,000 square miles, is the unit: Nine Thames equal one Elbe (54,000); two Elbes equal one Pechora (108,000); two and a half Pechoras equal one Danube (270,000); two Danubes equal one Mackenzie (540,000); two Mackenzies equal one Yenisei (1,080,000); two Yeniseis equal one Amazon (2,100,000). There is nothing that makes a greater impression upon the arctic traveler than the enormous width of the rivers. The Pechora is only a river of the fifth magnitude, but it is more than a mile wide for several hundred miles of its course. The Yenisei is more than three miles wide for at least a thousand miles and a mile wide for nearly another thousand. Whymper describes the Yukon as varying from one to four miles in width for three or four hundred miles of its length. The Mackenzie is described as averaging a mile in width for more than a thousand miles, with occasional expansions for long distances to twice that size.
Investigation of Earthquake Phenomena.—The committee of the British Association, appointed to investigate the volcanic and earthquake phenomena of Japan, has reported that the records of horizontal pen-