Why are there two Stefan Boltzmann Laws in Reif's book?

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Reif's book "Fundamentals of Statistical and Thermal Physics" presents two versions of the Stefan-Boltzmann Law, both involving T^4 but differing in constants. The formula on page 376 is (pi^2/15)*(kT)^4/(c*hbar)^3, while the one on page 388 is (pi^2/60)*(kT)^4/(c^2*hbar^3), with the latter being c/4 times the former. The distinction likely arises from one formula representing the intensity of emitted radiation and the other the energy density of radiation. This difference is crucial for understanding their applications in physics. The discussion highlights the importance of context when interpreting these formulas.
PatF
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In Reif's book Fundamentals of Statistical and Thermal Physics, he labels two formulas as the Stefan-Boltzmann Law. They are both involve T^4 but the constant is different. In one, on page 376, the law is given as (pi2/15)*(kT)4/(c*hbar)3.

The other, on page 388, is (pi2/60)*(kT)4/(c2*hbar3).

The second formula is c/4 times the first.

I have looked carefully through the text and I can't see why there should be a difference. What have I overlooked?
 
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Thanks much! I just checked and I think you are right.
 

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