Alchemists Approach Atlantis

it seems that of these 92 natural elements, only 88 can be considered naturally occurring since the above four are transient species, newly formed by radioactive decay. Neptunium and plutonium can similarly be found in ultratrace quantities due to de novo synthesis coupled to rapid decay. We could stretch a point by noting that all helium on our planet is also formed de novo. However, although these fresh helium atoms are lost into space, the nuclei are totally stable. 

The true stars of Seaborg s 1944 Periodic Table are the transuranium elements neptunium (Np) and plutonium (Pu) as well as elements 89 to 92 (actinium, thorium, protactinium, and uranium). Neptunium was synthesized by McMillan and Abelson at Berkeley in 1940. In late 1940 and early 1941 McMillan, Kennedy, Wahl, and Seaborg made Pu through bombardment of uranium with deuterons in early 1941, and Pu was obtained by bombarding uranium with neutrons. It was Seaborg who, m 1944, proposed a new series of compounds for the Periodic Table—the actinides—analogous to the rare earths or lanthanides. In his book The Periodic Kingdom, Atkins describes the lanthanides 

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