"E"
Scales 

Elem 
The Elem scale is a custom scale in
iSlideRule that provides the atomic mass of various natural
elements of the periodic table. The mass is read on
the D scale when both the Elem and D scale are on the top
and/or bottom rule. The color of the element on the
scale determines where to position the decimal point (how
many digits to the left of the decimal point). If the
element is shown in green,
there is a single digit to the left of the decimal
point. If the element is red,
there are two digits in the value that are to the left of
the decimal point. Blue
colored elements have three digits to the left of the
decimal point in their atomic mass. The Elem scale can only be placed on the top or bottom rules. 