Sub-project 3-5 -- Correlation of Basic Ventilation Data with Gun Fume Studies and Devalopment for the Control of Gun Fumes in the M4 Tanks : Subject -- Control of Gun Fumes in M4 Series Medium Tanks by Positive-pressure Ventilation. Supplement report on sub-project 3-1 -- Determination of the characteristics and effects upon the crew of gun fumes from firing of the weapons in tanks of the M4 series