AbstractGaseous eddy diffusivity measurements were made by a point injection technique in a 6.5‐in. column packed with open‐end screen cylinders varying in size from 3/8‐in. to 1 1/2‐in. diameter, and made from wire cloth varying from 4 to 28 mesh/in. Oxygen was used as the tracer gas. Only packings made from 4 to 10 mesh/in. produced concentration profiles which were symmetric. The latter data show that turbulent diffusivity increases linearly with gas flow rate, but decreases with decreasing mesh opening and wire diameter. A correlation is presented for turbulent diffusivities as a function of the Reynolds number,dmuρ/m̈, and the r