Table 403 {conHntied). 

 RESISTIVITIES AT HIGH AND LOW TEMPERATURES. 



(Ohms per cm. cube unless stated otherwise.) 



2Zi 



Pl. low, Nernst, 1. c. high, Pirrani, Ber. Deutscli. Phvs. Ges. 12, p. 305, Pb. low, Schimank, Nernst, 1. c. high. 

 Northrup, see Zii. I'.i. low, means, high, Norihrup, see Zn. Cd. low, Euchen, (jehlhoff, Verb. Deutscli. Phys. Ges. 14, 

 p. i6q, igi2, high, Northrup, see Zn. Sn. low, Dewar, Fleming, high, Northrup, see Zn. Carbon, graphite, Metallurg. 

 Ch. Eng. 13, p. 23, 1915. Silica, Campbell, Nat. Phys. Lab. 11, p. 207, 1914. Alundum, Metallurg. Ch. Eng. 12, p. 

 125. '9'4- 



* Diamond 1030O C, p >io'; 1380O, 7.5 x 10', v. \Vartenberg, 1912. 



TABLE 404.— Volume and Surtace Resistivity of Solid Dielectrics. 



The resistance between two conductors insulated by a solid dielectric depends both upon the surface resistance and 

 the volume resistance of the insulator. The volume resistivity, p, is the resistance between two opposite faces of a cen- 

 timeter cube. The surface resistivity, <r, is the resistance between two opposite edges of a centimeter square of the 

 surface. The surface resistivity usually varies through a wide range with the humidity. (Curtis, Bui. Bur. Standards, 

 "1 359, '9'5i which see for discussion and data for many additional materials.) 



Material. 



Amber 



Beeswax, yellow .... 



Celluloid 



Fiber, red 



Glass, plate 



" Kavalier .... 

 Hard rubber, new . . . 



Ivory 



Khotinskv cement . . . 

 Marble, Italian .... 

 Mica, colorless .... 

 Paraffin ((jarowax) . . . 

 Porcelain, unglazed . . , 



Quartz, fused 



Rosin 



Sealing wax 



Shellac 



Slate 



Sulphur 



Wood, parafined mahogany 



<T ; megohms 

 50% humidity. 



6 X 10* 



6 X 10* 

 5 X 10* 



2 X 10* 

 5 X 10* 



4 X 106 



3 X io9 



5 X io3 



7 X 108 

 3 X io» 



2 X 10^ 

 9 X io9 



6 X 10^ 



3 X 106 

 6 X io» 

 2 X io9 



6 X 10'' 

 9 X 10 



7 X io9 



4 X lo'^ 



<r ; megohms 

 70% humidity. 



2 X 10* 



6 X 108 



2 X 10* 



3 X io3 

 6X 10 



4 X 108 

 I X 108 



1 X 108 

 3 X 108 



2 X io2 

 4X 10^ 



7 X io9 

 7 X 108 



2 X 108 



3 X 10* 

 6X 10* 

 3 X io« 

 3X 10 

 4X lo* 

 SX io5 



<r ; megohins 

 90% humidity. 



1 X 



5X 



2X 



2 X 

 2 X 



1 X 



2 X 



3X 

 SX 

 2 X 

 8X 

 6X 

 SX 

 2 X 

 2 X 

 9X 

 7X 

 I X 

 I X 

 7X 



Megohms-cms. 



5 X io"> 



2 X lO^ 

 2 X 10* 



5 X 108 



2 X 10" 



8 X io9 



1 X 10I2 



2 X I02 

 2 X I09 



1 X lo^ 



2 X 10" 



I X loi" 



3 X 108 

 S X 10I2 

 5 X ioi'5 

 8 X io« 

 I X loi" 

 I X io2 

 I X to" 



4 X lo^ 



i Smithsonian TablcSi 



