THE ENERGY CONDITIONS NECESSARY TO PRODUCE 



THE RONTGEN RAYS. 



By John Tkowbridge. 



Presented March 10, 1897. 



This paper is a preliminary study of the conditions which exist in 

 hif^hly rarefied media under discharges of electricity, conducted by means 

 of the large storage battery of the Jefferson Physical Laboratory. 



The value of a large storage battery for the study of the discharge of 

 electricity through gases has long been recognized, and such batteries of 

 1,800 to 2,000 cells have been constructed by Zehnder, by Quincke, 

 and others. Quincke devotes a large portion of a recent article* to 

 a description of the details of construction of such a battery of 1,200 

 cells. The battery of the Jefferson Physical Laboratory consists of 

 10,000 cells, and it is of such practical construction that I believe a 

 detailed account of it will be of advantage to those contemplating the 

 installation of a similar one. When I was considering the cost of such 

 a battery, Professor B. O. Peirce, my colleague, expressed the opinion 

 that dry wood would serve perfectly well for insulating material ; and 

 the mechanician of the Laboratory, Mr. G. "W. Thompson, coinciding in 

 this opinion and deprecating the use of vulcanite or any of the forms of 

 insulators in the market, on account of the loss of insulation due to sur- 

 face action, I decided to adopt wood for the supports of the cells of the 

 battery. 



There are 10,000 cells, each one consisting of a test tube 5 J inches 

 long and 25 mm. diameter, shown in elevation and plan in Figure 1 

 and Figure 2. The plates of the cell are strips of lead 1 mm. thick, 

 12 mm. broad, which have been run through a peculiar mill to give 

 them a corrugated surface. The strips do not reach to the bottom of 

 the tubes, in order to avoid short circuiting due to a possible falling 

 off of the peroxide of lead. They are separated by rubber bands, B, and 



* Annalen der Physik und Chemie, No. II. p. 417, 1896. 



