Gene Fuller wrote:
"Terman certainly did not deny the existence of skin effect that keeps
fields out of the interior of conductors.'

true. The point is, shielding from magnetic fields is different from
electric fields. On page 35 of his 1955 edition, Terman writes:
"Magnetic flux in attempting to pass through a shield (copper or
aluminum) induces voltage in the shield which gives rise to eddy
currents. These eddy currents oppose the action of the flux, and in
large measure prevent its penetration through the shield."

On page 38, Terman writes:
"Electrostatic shielding is obtained by enclosing free space to be
shielded by a conducting surface."

On page 45, is problem 2-45 which contains an illustration of a grid of
open-circuit wires which "will provide electrostatic shielding without
magnetic shielding---." This works just like the picket fences used in
broadcast stations to inhibit harmonic transmission.

Terman did not make this stuff up. It was already in wide use at the
time.

Best regards, Richard Harrison, KB5WZI