HOW TO LIGHT LARGE CITIES. THE PRESIDENT: As there is a delay in making ready for the next paper, I would suggest that we take up the topic "How to Light Large Cities;" and after that we will go on with Dr. Bell's paper. We should like to have Mr. Wilmerding address the meeting on this topic. MR. WILMERDING: The cost of lighting in Chicago, according to Professor Barrett's figure of a year ago, if I remember rightly, was $96.25 per lamp. This figure it is stated, included nothing of interest, depreciation, insurance, taxes, etc., or what in a lighting company would be called general expense. In other words, it might be said to include solely labor and material. The cost per lamp installed was something in excess of $500, which at six per cent interest on the original investment would amount to $30, and a fair depreciation might be six per cent, which would add another $30, or a total of $60, to the cost; in other words, about $156 per lamp per annum. We are furnishing a few lamps to the city at $137.50 per annum, so that, as a matter of fact, we are supplying light at a lower cost to the city than they can make it themselves. On that basis, it seems reasonable to suppose that large cities should be lighted by private corporations rather than by the city itself. There is no question but that in every municipal organization in this country the cost of carrying on what may be considered a commercial or private business, is much greater than where it is carried on by a private corporation where all expenses are carefully considered. MR. REDMAN: I think the best answer I can give to this question is to give a description of the city lighting by the two companies with which I am connected. The city of Rochester, with a population of 165,000; has 2,010 arc lights on the streets; 1,109 on the Brush Electric Company's circuits and 901 on the Rochester Gas and Electric circuits. In the centre of the city we have one street, 7,940 feet in length, with no wooden poles, and no overhead construction except the trolley wire. That street is lighted with seventy-six pairs of eight-ampere lamps, on the Edison system, which give general satisfaction. They are so popular that the cry is for lighting the entire city on that system. Dr. Louis Bell then read his paper, as follows: THE MONOCYCLIC SYSTEM. To the central station man, no recent change in engineering practice can have more interest than the renaissance of alternating current work that is now in progress. Truth to tell, until quite recently the alternating current was somewhat under a cloud in the estimation of both station managers and engineers. It has served an immensely useful purpose in the extension of electric lighting to places where it would have been utterly impracticable to install a direct current system of any sort, on account of the scattered nature of the work. A very large number of stations have been installed on the alternating system, and I am sorry to say that a large proportion of them have been somewhat unsatisfactory, not in their general operation, but in the character of their service and the commercial results. It is quite common to find alternating stations with a plant efficiency considerably below and in and in which which the regulation is within ten per cent. fifty per cent, maintained only Under these circumstances, it is small wonder that the advocates of the direct current, the uses of which as an engineering problem have been have been very completely worked out, have often been somewhat violent in their animadversions on alternating currents in general. Nevertheless, in the last two or three years there has been a vast change for the better in alternating practice, a change not yet rapid, but bidding fair · to be far-reaching. This change has taken up a three-fold path toward progress. First, the use of large transformers is becoming more frequent; next, these transformers are more and more used in conjunction with systems of secondary mains; and, finally, it is now possible to install an alternating plant that shall be able to operate motors as successfully as can be done with. direct current. In ordinary central station practice, the motor service does not usually play a very important part; nevertheless, the ability to run motors is most valuable. It is more profitable, speaking broadly, to sell current for light, for a better price per kilowatt hour can be obtained; at the same time, if motors can be readily furnished, a useful day load can be obtained when it is needed, and the plant becomes the greater service to the community; a thing which, in these days of friction with common councils, is of no small importance. Not only can motors now be successfully worked off alternating circuits, but off circuits, but off a wide variety of such circuits. As yet, however, there is no successful motor for use on the simple alternating system that has, for for the most part, been installed in this country. While it is possible to construct a singlephase motor for even 120 to 130 cycles per second, -the frequency most used in America-it is at present very doubtful whether such a motor can be made to start and run in a way that will be generally satisfactory. Abroad, where low periodicities are used, better results can be obtained; but, even there, there is a noticeable silence on several important points in describing alternating motor practice. Appearances indicate that, that, even with the advantage of low frequency, motors for use on simple alternating |