Thank you. It sounds like "atomic weight" would have been a better term?
This is not related to my original question, but I was confused by this passage:
"... we cannot forget that within the interior of our world, underneath the surface of the Earth, there are seven submerged atomic regions that relate to the atomic infernos of Nature, since the Holy Heptaparaparshinokh—the law of seven—is fundamental in everything created."
Why does Master Samael state there are seven regions when there are nine?