PRESSURE ON RESISTANCE OF METALS. 



643 



TABLE XXV. 



Pressxtre Coefficient of Specific Resistance Calculated bv 



GrUNEISEN's FORJtULA. 



Metal 



Compressi- 

 bility 



V \CPI T 



in kg 



Thermal 

 Expan- 

 sion 



'{-) 



v\CtJp 



Temp. 

 Coeff. of 

 Specific 

 Resist- 

 ance at 

 0°C 



Specific 

 Heat 



Cp 



kg. cm. 

 per cm' 



Pressure Coefficient of Specific 

 Resistance 



Computed 

 Griineisen 



Observed 



Computed 



Beckman 

 with G's 

 formula 



In 

 Sn 

 Tl 

 Cd 



Pb 



Zn 



Mg 

 Al 



-^g 

 An 



Cu 



Xi 



Co 



Fe 



Pd 



Pt 



Mo 



Ta 



W 



2.0(?)X106 .O3I3 

 1.86 I .O45I 

 2.26 I .0^92 

 2.06 .O49O 



2.28 



1.66 



2.84 

 1.44 



.99 



.63 



.735 



.42 



(.oO)(?) 

 .58 

 .53 

 .27 

 .45 

 .52 

 265 



. 0^879 



.O478 



.O478 

 .O474 

 .O455 

 .O443 

 .O451 



.00404 I 17.5 

 433 17.2 

 520 16.4 

 407 20.3 



409 I 14.9 



I 

 407 ' 27.8 



396 

 433 

 406 

 392 

 431 



18.3 

 24.1 

 24.9 

 25.6 

 35.2 



40.9 



37.8 

 35.3 

 30.0 

 29.3 



24.8 

 23.1 



27.7 



.O4I37 ?) 



.06464 



.O4II3 



.0^728 



.O4IO2 



.O5427 



. 0a601 

 .0a536 

 .O5372 

 .O5292 

 .06241 



.06206 



.O4I29 

 .O4IIO6 

 .O4I39 

 .O4II32 



.O4I52 



.06595 



.0655 



.06464 



.06383 



.O5333 



.O5245 



.06172 



I 



.06672 



.0682 



.0671 

 .O4II7 

 0698 

 O4IO4 

 .06488 

 .05276 



.06423 

 .06384 

 .06279 

 .06211 

 .06193 

 .O5I57 



absence of measurements, as fitting well into the periodic table as 

 shown by Richards. ^^ Also the compressibility of cobalt has not been 

 measured; I have assumed a mean between iron and nickel. 



For comparison, the computed values of Beckman, reduced from 

 atmospheres to kilograms, are reproduced in Table XXV. It-appears 

 that the revised values sometimes give better and sometimes poorer 



