4o8 



Tables 528-529. 



TABLE 628. —Miscellaneous Constants (Fundamental, Atomic, Molecular, etc.). 



c Velocity of light in vacuo 29QS60 Km/sec. 



y Newtonian gravitational constant 6.658 X lo-s cmVg.sec.* 



e electronic charge 4-774 X 10-'° esu. 



1. 591 X iQ-^Oemu. 

 1.591 X 10-" coulombs. 



mo mass isolated electron at rest 8.9999 X lo-^s g 



mp mass of proton in heavier elements 1.649 X 10-" g 



mn mass neutral H atom at rest, i.ooSmp 1.663 X 10- ^^ g 



h Planck's quantum of action 6.554 X lo-^' erg. sec. 



e/mo small velocities or at rest, Bucherer's constant 1.769 X 10' emu g-i 



5.307 X 10" esu g-i 



F Faraday constant, loNe/c ._ 96500 coulombs 



N Avogadro's constant, no. molecules per g molecular weight 6.061 X 10-^ 



n Loschmidt's number, no. molecules per cm^ 0°C, 76 cm 2.705 X 10" 



No. molecules per cm^, 0°C, lo^ bars 2.670 X lo'* 



Radius of electron about 2 X io~'^ cm 



Radius of H molecule about lo-s cm 



L Mean free path H molecule 76 cm 0°C about 1.6 X iQ-^ cm 



G Sq. rt. mean sq. velocity ditto about 1.84 X 10^ cm/sec. 



Q, Arithmetical average velocity ditto about 1.70 X lo^ cm/sec. 



No. ditto striking i cm- per sec, 25° C, i bar 10.82 X iqI' 



Average distance apart of molecules 76 cm 0°C 3 X lo-^ cm 



Absolute zero, centigrade scale, 0° K —273.1° 



Vo Vol. per mol(e) or g. molecular, weight ideal gas: 



76 cm. 0° C (1,013,230 dynes /cm^) 22.412 cm' 



10^ dynes, 0° C 22.708 cm' 



po atmosphere, 76 cm Hg, 0° C 1,013,230 dynes/cm^ 



Eo Kinetic energy of translation of molecule at 0° C, (3/2) (poVo/N) 3-620 X 10-" erg 



e Constant of molecular energy, change of translational energy per °C, Eq/T 2.058 X lo-'^ erg/°K 



k Boltzman gas constant, constant of entropy equation, R/N = (2/3)6 1-372 X io-'» erg/°K. 



R . Gas Constant in PVm = RT: 



Vm = molecular weight in g; P in g/cm^, Vm, cm^ 84.77 g- cm/°K 



atm., 1 0.08206 1. atm./°K 



dynes, cm' 8.315 X 10' erg/°K 



calorimetric units 1.9869 cal (i5°)/g. mol. 



I megabar f = Meteorological "bar") = lo^ dynes/cm^ = 1.013 Kg/cm^ 0.98694 atm. 



Mechanical equivalent of heat, g. (20° C) calorie 4.180 intern, elec. joules 



g. (20° C) " 4-181 X 10' ergs 



g. (15° C) " 4.18s X 10' ergs 



Ct Atomic heat solids (D and P), sNk 24.95 joules per mol.°K 



Cvo Molar heat perfect gas, constant volume (3/2)R 2.979 cal per mol.°K 



Cpo Molar heat perfect gas, constant pressure (s/2)R 4-q6s cal per mol.°K 



Cv Atomic heat solids, D and P, 3R 5-9S8 cal per mol.°K 



Roo Rydberg fundamental frequency 3-277S X lo's sec.-i 



Rydberg's constant, Roo /c (Bohr) 1-0930 X lo^ cm-' 



o- Stefan-Boltzmann constant, total radiation 5-7i X 10-12 watt-cm^ 



Co Wien's constant of spectrum radiation ch/k 1.4325 A in cm. 



c, Planck's constant of radiation, 20% 3-703 X 10-6 erg/cm^ sec 



Photo-electric quantum ch/e 4-117 X 10-' esu erg/°K 



Thermo-electric quantum k/e 2.874 X 10-' esu erg/°K 



AmT Wien's displacement constant C2/4.96S1 0.2885 cm°K 



M Mechanical equivalent of light 0.00150 watt/lumen 



Calcite grating space 3-028 Angstroms 



Standard gravity 980.665 cm/sec.2 



Mean solar second 1.00273791 sidereal sec. 



TABLE 529. — Radiation Wave-length Limits. 



t 



Hertzian waves, longest 2 ckw ocio.o cm 



" " shortest ;■■••. 0.2 cm 



Infra-red, longest, reststrahlung, focal-isolation 0.03 cm 



Infra-red, spectroscopically studied 0.002 cm 



Visible, longest o-°oo 08 cm 



shortest 0.000 04 cm 



Ultra-violet, Lyman, shortest* o-ooo 006 cm 



X-rays, longest 000° °°° 12 cm 



" shortest 0.000 000 001 cm 



V rays, longest .."!.'.'.'.".'.'.'.'.'.'.'.'..'.."..'!."..".!......'...'.." 0°°° °°° °i3 cm 



shortest °-°°° °°° o°o 7 cm 



* 0.000 0020 cm (Millikan-Sawyer, 1920) 

 Smithsonian Tables. 



