  Binary fission induced by 140 MeV $\alpha$-particles has been measured for
$^{\rm nat}$Ag, $^{139}$La, $^{165}$Ho and $^{197}$Au targets. The measured
quantities are the total kinetic energies, fragment masses, and fission cross
sections. The results are compared with other data and systematics. A minimum
of the fission probability in the vicinity $Z^2/A=24$ is observed.
