As I suggested in my comment, it was both a little archaic, and also you took it out of context.
It doesn't make sense without more of the sentence:
"not a step was taken but was heralded by glasses round"
In more modern English, that would be "not a step was taken that was not heralded by glasses around".
Based on the original, I think that 'step' here means 'phase of the preparations'. And in other words, they toasted (with drinks) each step in the planning of the journey.