CONTENTS Vll 



38. Elliptic integrals : Values of 7 (1 — sin 2 Oi) sin 2 $)±^$ 71 



.' o 



39. Moments of inertia, radii of gyration, and corresponding weights . 72 



Birge's Physical Constants 



40. Probable values of the general physical constants 73 



The velocity of light in vacuum (c) [2.99796 cm/sec. | .... 74 



Newtonian constant of gravitation (G) [6.664 dyne cm 2 /g _2 | • 75 



Mean density of the earth [5.522 g/cm -3 ] 75 



Relation liter to dm 3 [1.000027 dm 3 ] 75 



Normal mole volume of ideal gas [R n a , 22.4135 //mole] ... 75 



Ratio international to absolute electrical units yy 



Atomic weights of certain elements 81 



H, p. 81 ; He, N, Ag, p. 82 ; I, C, p. 83 ; Ca, p. 84. 



Normal atmosphere, A n [1.013249X io 6 dyne/cm 2 ] 84 



Absolute temperature of ice-point (T ) [273. 18 K. | . . . . 85 



Mechanical equivalent of heat (/); electrical, (/') 86 



The faraday (F) [96489 abs. coul.] 87 



Electronic charge (e) [4.770 x io -10 abs. e.s.u.] 88 



Specific charge of electron (e/m) 92 



Planck constant (h) [6.547 X io -27 erg/sec] 94 



Fundamental constants, Birge 103 



41. Powers of c, h, e, h/c 103 



42. Additional constants used by Birge in connection with Table 40 . . 104 



43. Miscellaneous derived physical constants, Birge 105 



44. Volume of glass vessel from weight of its volume of Hg or H 2 . 108 



45. Reductions of weighings in air to vacuo 109 



46. Reductions of densities in air to vacuo 109 



47 

 48 



49 

 50 

 5i 



52 

 53 

 54 

 55 

 56 

 S7 

 58 



Mechanical Properties 



Introduction and definitions no 



Ferrous metals and alloys : Iron and iron alloys 1 1 1 



" Carbon steels 112 



" " " Heat treatments 112 



Alloy steels 113 



Steel wire — specification values . . 114 



" " " " " " experimental values . . 114 



Semi-steel 114 



Steel-wire rope — specification values. 115 



" " " " " " " experimental values. 115 



" Plow-steel rope [specification values] 115 



Aluminum 116 



