He said that Venus, being a young planet, was at the boiling point of lead. Science at the time thought it was only slightly warmer than Earth. Vel. was right. Assuming you've accurately presented his theory here, he was only "right" for fairly flexible values of "right" - the surface temperature of Venus is less than 1/3 of the boiling point of lead, 900 ºF, versus almost 3200 ºF for lead's boiling point.
Yes, it has been a while since I read him. My numbers could be off, but the point remains.