77 



in the Laboratory of Purdue University were taken by Mr. Adam Herzo"- 

 B. M. E., a summary of which is as follows: 



First, measurements were taken from a 15 x 24 Corliss engine ; this machine 

 has unusually massive parts, the frame being a heavy girder, and the whole 

 being mounted in an excellent manner upon a deep foundation. Observations 

 were made while the engine was developing only 35 horse-power with an 

 initial steam pressure of 80 pounds. The head end of the cylinder was found to 

 move in a horizontal direction with every revolution of the engine, x distance of 

 0.009 of an inch; the frame over the guides moved in a vertical direction 0.014 

 of an inch, and the pillow block castings in a horizontal direction 0.030 inches. 



Secondly, measurements from a 14x16 engine, having a modification of the 

 box-bed, mounted upon a substantial foundation, cajjped by a single stone of 

 massive size. The details of the engine are heavy and well designed. Its center 

 line, however, is considerably above the line of resistance ofTered by the bed. 

 Observations were taken during a time when the engine was running under an 

 initial pressure of only 40 pounds and Avhile developing only 14 horse-power 

 which is less than half its rated power. The head end of the cylinder was found 

 to move horizontally 0.018'^, and the top of the cylinder at the flange on the 

 crank end to move vertically 0.022^'. 



These vibrations, while taking place Avith every stroke of the engines, would 

 not ordinarily have been detected with the eye, and were not accompanied by any 

 shock or other manifestation which would indicate their presence. The measure- 

 ments will serve to show to what extent the heavy fixed parts of well-designed 

 machines may move under the influence of the forces which they are designed to 

 resist, and they emphasize tlie necessity for a distribution of the metal which will 

 give strength in direct line with the stresses to be transmitted. 



Viscosity of a Polarized Dielectric. By A. Wilmer Duff. 

 [Abstract.] 

 Very few observations of mechanical actions produced in liquid dielectrics by 

 electro-static stress have been made. Faraday found that fibres of silk in the 

 liquid set themselves along the lines of force. Quincke thought he had detected 

 an alteration of volume, but his results have been doubted. Konig tried to find 

 a variation of viscosity by finding the rate of fiowthrough a capillary tube placed be- 

 tween charged plates, but failed. A limit was set to the accuracy of his method 

 by the diflSculty of maintaining the tube at a constant temperature. 



