Two Part C corrections

[khardy]

On p. A-8 of Ch. 12 (first sentence), the calibration factor calculation references eqn. 10-18. This should be changed to eqn. 10-10.

Also on P. A-8, the equation N spf int shows exp (-5.73 + …) while the correct equation (10-10) on p. 10-20 shows exp (-5.13 + …). This error seems to be propagated through the example calculations on p. A-8 and A-9.