We report a new measurement of dijet production by color-singlet
exchange in ppbar collisions at sqrt s = 1.8 TeV at the Fermilab Tevatron, and
present results on the dependence of the cross section on jet transverse
energy and pseudorapidity separation between the jets.  In a sample of events
with two jets of transverse energy E^jet_T > 20 GeV, pseudorapidity in the
range |eta^jet| < 3.5, and eta_1 eta_2 < 0, we find that a fraction R = 1.13
+/- 0.12(stat) +/- 0.11(syst)% have a pseudorapidity gap within |eta| < 1
between the jets that can be attributed to color-singlet exchange.  The
fraction R shows no significant dependence on E^jet_T or on the pseudorapidity
separation between the jets.