766 



SCIENCE. 



[N. S. Vol. XXIII. No. 594. 



which the pointer is fastened, and which 

 carries the condenser current, is mounted 

 either directly above or below the bobbin 

 which carries a graduated scale. Advan- 

 tage is taken of the fact, suggested by Mr. 

 Begole, that the instrument is a combined 

 voltmeter and frequency-meter. 



Carl Kingsley, of the department of 

 physics. University of Chicago, presented a 

 paper which was read by abstract on 'A 

 Critical Analysis of the Methods of Sup- 

 plying Power to Branch Telephone Ex- 

 changes on the Common Battery System.' 

 The five possible methods are considered, 

 and three of these are chosen as most 

 worthy of critical analysis. In each of 

 the three cases the total costs are deter- 

 mined in terms of the distance from the 

 central and the total energy to be supplied 

 at the branch exchanges. Three equations 

 are obtained, each of which contains the 

 three variables, cost, distance and energy. 

 For any particular exchange, the method of 

 supply can be, therefore, readily chosen, 

 which will give the minimum cost of opera- 

 tion. Complete curves have been drawn 

 and a graphical solution of the problem 

 can be obtained by inspection. 



D. S. Jacobus, professor of experimental 

 engineering, Stevens Institute, Hoboken, 

 N. J., read and illustrated a paper giving 

 the results of his experiments on ' The Dif- 

 ference in the Coefficient of Discharge of 

 Steam through a Single Circular Orifice 

 in a plate and through a Number of Cir- 

 cular Orifices in the Same Plate.' 



The flow of steam through an orifice in a plate 

 was determined and compared with that obtained 

 when six orifices of the same size were placed 

 near each other in the same plate. The flow per 

 orifice was about 14 per cent, greater than with 

 a single orifice. This shows how important it 

 is to consider the conditions which exist on the 

 exhaust side of the orifice. The experiments also 

 showed that the position at which the pressure 

 on the exhaust side of the orifice was measured 

 was an important factor, as this pressure varied 



considerably when measured at different distances 

 from the orifice plate. 



The orifices were %" in diameter. The pipe 

 conveying steam to the orifice plate and conduct- 

 ing it away from the same was 2" standard size. 

 The orifice plate was placed in a flange union. 

 The single orifice was at the center of the plate 

 and the six orifices were arranged with one orifice 

 at the center and five midway between the 

 periphery of the center orifice and the inside of 

 the pipe. The pressure on the high-pressure side 

 of the orifice was about 147 pounds per square 

 inch, and on the discharge, or low-pressure, side, 

 about 105 pounds per square inch. The pressure 

 on the discharge side was measured at a consid- 

 erable distance from the plate in order to avoid 

 a jet action which existed at a point near the 

 plate, which caused the pressure near the plate 

 to be less than at some little distance from the 

 plate. 



In a second paper he discussed the sub- 

 ject of 'Priming caused by Poor Circula- 

 tion in a Boiler,' and described experiments 

 which he had made. 



A small vertical tubular boiler of about fifteen 

 rated horse-power was employed in the experi- 

 ments. This boiler was of the ordinary con- 

 struction with a water heating surface enclosing 

 a circular grate and with tubes leading directly 

 upward from the combustion space above the 

 fire to the upper tube sheet at the top of the 

 boiler. The steam was taken from the boiler at 

 a point in the outer shell near the top of the 

 boiler. When the boiler was run under normal 

 conditions the steam generated was dry for ordi- 

 nary rates of combustion, and superheated when 

 the boiler was forced to a high capacity. 



In this class of a boiler, the temperature of 

 the flue gases escaping from the tubes near the 

 center of the tube sheet is much higher than that 

 of the gases from the outer tubes, and tests were 

 projected to determine whether there should be 

 a gain in the economy through placing retarders 

 in the center tubes so as to more evenly distribute 

 the work done by the different tubes. In these 

 tests the retarders were so adjusted that the tem- 

 perature of the escaping gases was made about 

 the same for each of the tubes. After this was 

 done there was an unexpected action through the 

 boiler priming so severely that it was impossible 

 to run it at other than a low capacity. The 

 water level would be constant for a short time 

 and the steam would be dry, when suddenly foam 

 would appear in the gauge glass and water would 



