Page:Popular Science Monthly Volume 43.djvu/298

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286
THE POPULAR SCIENCE MONTHLY.

tivating medium for their propagation; but a suitable condition of the atmosphere exists only under certain exceptional circumstances. This accounts for the rapid spread of cholera among large masses, especially dirty masses, of men. Each unit of infection acts on suitable media exactly as would a particle of yeast if introduced into a mass of fermentible fluid under the requisite conditions of temperature, etc. This is the explanation of the fact that, although cholera may arise sporadically anywhere, under favorable but exceptional circumstances, it is endemic only in India, where, presumably, these requisite conditions constantly prevail. That cholera does spread principally along the lines of human intercourse, that it may be conveyed by man, by water, by fomites, may be readily conceded without affecting the contention as to its miasmatic and aërial character and method of propagation. That cholera is caused by Koch's vibrio is to the last degree improbable, and certainly unproved, and the presence of that microbe in the dejecta of cholera patients may be due simply to its finding a congenial soil there.

 

Progress in Practical Electricity.—The recent inaugural address of Mr. W. H. Preece, as President of the English Institution of Electrical Engineers, was devoted to a review of the progress of the practical applications of electricity during the forty years of the speaker's service in developing them. He spoke first of the extension of the telegraph; then of the oceanic service of the Eastern Telegraph Company, the greatest cable corporation in the world, whose system of 25,370 miles stretched from Cornwall to Bombay, connected the northern and southern shores of the Mediterranean with Malta, and joined the various other islands of the Mediterranean and the Levant. This company, in conjunction with the Eastern Extension and the Eastern and South African Companies, also gained access to Australia and New Zealand on the one hand, and the Cape of Good Hope on the other, the combined mileage reaching a total of 47,151 miles. There was no more perfect apparatus in existence, the speaker said, than the lightning protector, and if it ever failed to do its duty it failed from man's neglect of some simple rule or his failure to keep it in proper order. In 1892 not an accident was recorded in any high-class telegraph instrument in the whole United Kingdom. To railways, electricity had proved an invaluable adjunct—in the repetition of signals obscured from the view of the signalman, and in night signals. The number of telephones in actual use might be put down at a million. The speaker had recently devised a new form of cable which would probably quadruple the rate of telegraphic cable working to America. There was no theoretical reason why we should not converse between London and every capital in Europe, while it was not impossible to speak even across the Atlantic. Heating and cooking apparatus worked by electricity had not at present a very favorable outlook, though many appliances had been shown in operation. The electric light was essentially the poor man's light. Many efforts were being made to utilize the waste forces of Nature in producing electric currents for the economical supply of the light. There were many towns whose streets could be brilliantly illuminated by the streams running past them. The range of power transmission had been enormously extended since much higher voltages than were possible with continuous currents could be employed. Meanwhile, power transmission by single-phase alternating current had also been developed. The use of electrically transmitted power in mines had been greatly extended within the last few years, especially in America, and the use of electrical energy for working railways was making gigantic progress in the United States, while it had begun to make a serious move in the United Kingdom.

 


NOTES.

In his article in the April number of The Popular Science Monthly entitled Science and the Colleges, President D. S. Jordan made the statement that "it is not many years since the faculty of one of our State universities spent a whole afternoon discussing the proposition to abolish laboratory work in science." He now writes us that although the statement was given on what he regarded as good authority, he has been informed by a member of the faculty of the institution in question, who took part in the discussion, that the question was not whether laboratory work should be abolished, but simply whether, in the course leading to the degree of B. A., laboratory work should not