Page:Popular Science Monthly Volume 42.djvu/442

426 available. When textile manufactures began to pass from the condition of purely domestic industries to that of a factory system, the principal mills were erected near river falls, no other power than water power having been found practically useful. "About 1790," says Mr. Kennedy, "Mr. Watt's steam engine began to be understood, and waterfalls became of less value. Instead of carrying the work-people to the power, it was found preferable to place the power among the people." The whole tendency of the conditions created by the use of steam power has been to concentrate the industrial population in large communities, and to restrict manufacturing operations to large factories. Economy in the production of power, economy in superintendence, the convenience of the subdivision of labor, and the costliness of the machines employed, all favored the growth of large factories. The whole social conditions of manufacturing centers have been profoundly influenced by these two conditions—that coal for raising steam can be easily brought to any place where it is wanted, and that steam power is more cheaply produced on a large scale than on a small scale. It looks rather, just now, as if facilities for distributing power will to some extent reverse this tendency. Water power, where it is available, is so much cheaper and more convenient than steam power that it has never been quite vanquished by steam power.

Electric Units.—The committee of the British Association on electrical standards have proposed the following resolutions, with a view to their adoption internationally: "(1) That the resistance of a specified column of mercury be adopted as the practical unit of resistance. (2) That 14·4521 grammes of mercury in the form of a column of mercury 106·3 centimetres long at 0° C. be the specified column. (3) That standards in mercury or solid metal having the same resistance as this column be made and deposited as standards of resistance for industrial purposes. (4) That such standards be periodically compared with each other, and also that their values be redetermined at intervals in terms of a freshly set up column of mercury." With regard to the units of current and electromotive force, it was agreed that the number ·001118 should be adopted as the number of grammes of silver deposited per second from a neutral solution of nitrate of silver by a current of one ampere, and the value l·434 as the electromotive force in volts of a Clark cell. Prof. Ton Helmholtz expressed his full concurrence in these decisions.

Power of Hypnotic and Vernal Suggestion.—Some most remarkable instances, taxing credulity, of the power of hypnotic suggestion were related at the recent International Congress of Experimental Psychology in London. A communication from Dr. Liebault told of a case of suicidal monomania cured by suggestion, the effect of which he hoped would be, with a few renewals, durable. In such cases the practitioner insists on making repeated affirmations of cure and multiplying the séances. Prof. Delbœuf had removed pain by causing the patient to exercise his will, and had cured a woman possessed with the idea of killing her husband and children—charming away the morbid thought by degrees for two hours, then for a day, and then for a week. Dr. Bramwell, of Goole, presented four of his patients in proof of his claim that he could command pain away by the mere spoken word, without inducing the hypnotic trance. He had recently painlessly extracted seven teeth from the woman of the group by merely ordering her not to feel pain; but failed in the eighth tooth, because she had previously formed the conviction that she would feel pain, so that her self-suggestion overbore his suggestion. The same patient had suffered from myopia, being able to read only the third line in the ordinary table of test letters. On his suggestion she had been able to read all the lines; and he could put her into the myopic state or relieve her from it by the word of command. He had been able to produce the same satisfactory results with all his patients by the mere command in a waking state that he had previously produced in a trance. The mere fact of his giving a written order to a patient to sleep enabled the patient to take that order, read it, and go to sleep whenever he needed to do so. He had repeatedly sent patients to a dentist carrying with them a written order not to feel pain, which they read when they sat down in the dentist's chair. He had now patients who