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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 suit- 

 able media exactly as would a particle of 

 yeast if introduced into a mass of fermenti- 

 ble 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 con- 

 tention as to its miasmatic and aerial charac- 

 ter and method of propagation. That chol- 

 era is caused by Koch's vibrio is to the last 

 degree improbable, and certainly unproved, 

 and the presence of that microbe in the de- 

 jecta 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 cor- 

 poration in the world, whose system of 25,3*70 

 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 Mediterra- 

 nean and the Levant. This company, in con- 

 junction 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 ac- 



cident was recorded in any high-class tele- 

 graph instrument in the whole United King- 

 dom. To railways, electricity had proved an 

 invaluable adjunct — in the repetition of sig- 

 nals obscured from the view of the signal- 

 man, and in night signals. The number of 

 telephones in actual use might be put down 

 at a million. The speaker had recently de- 

 vised a new form of cable which would prob- 

 ably quadruple the rate of telegraphic cable 

 working to America. There was no theoret- 

 ical reason why we should not converse be- 

 tween 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 opera- 

 tion. 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 econom- 

 ical supply of the light. There were many 

 towns whose streets could be brilliantly il- 

 luminated 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 alternat- 

 ing 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 discuss- 

 ing the proposition to abolish laboratory 

 work in science." He now writes us that al- 

 though the statement was given on what he 

 regarded as good authority, he has been in- 

 formed 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 



