August 4, 1952

The boron curtain has an area^a of 55 ft², and is 1/2" thick.
thus the volume is 2.3 ft³. Assuming that the maximum packed
density is 1.73 gm/cm³, the weigh needed is 250 lb.
Since we plan to mix it with paraffin, the density will not be that
high, so somewhat less will be used. I propose we order:

• 200 lb 60F Metallurgical grade Boron carbide
  @ $500/lb = $1000.
• Norton Company
• Worcester 6, Mass.

^aOne panel 5' x 5'; 4 panels 5' x 1 1/2'. See sketches attached,
which have been Mr. Griffin's hands for a couple of months.