2l8 



TABLE 238. 

 LINEAR EXPANSION OF THE ELEMENTS- 



In the heading of the columns / is the temperature or range of temperature; C is the coefficient of linear expansion; 

 A\ is the authority forC; M is the mean coefficient of expansion between o and 100 C; a and are the coefficients 

 in the equation It = fc(i + at + /8t 2 ), where lo is the length at o C and It the length at t C; At is the authority for 

 a, ft, and J/. See footnote for Molybdenum and Tungsten. 



References: (i) Fizeau; (2) Calvert, Johnson and Lowe; (3) Chatelier; (4) Henning; (5) Dittenberger; 

 (6) Matthiessen; (7) Andrews; (8) Holborn-Day; (9) Benoit; (10) Pisati and De Franchis; (n) Hagen; (12) 

 Spring; (13) Day and Sosman; (14) Griffiths; (15) Dorsey; (16) Griineisen. 



Tungsten: (L - Lo)/Lo = 4.44 X io~(r - 300) + 45 X io~"(r - 300)" + 2.20 X io~ l3 (T - 300)'. Lo = length 

 at 300 K. Coefficient at 300 K = 4.44 X io~*; 1300 K, 5.19 X IQ-; 2300 K, 7.26 X ie>-. Worthing, Phys. Rev. 

 1917- 



Molybdenum: Li = L*(i + 5.151 X io~ + 0.00570** X io-), for 19 to -142 C; 

 0.00138* X io-J, for io 8 Jto + 305 C; Schad and Hidnert, Phys. Rev. 1919. 



The Holborn-Day and Sosman data are for temperatures from 20 to 1000 C. 

 SMITHSONIAN TABLES 



Lo(i+ s.oi/X 10-0 

 The Dittenberger, o to 600 C. 



