Leaps and bounds

[Johnyxxx]

Hello,

I am not certain if I understand the bold text right. I know what the idiom in leaps and bounds means, so does the author wants to say the corrosion works sometimes quicker so the final number is higher than those three or four feet a year?

First, the sea out there. Are you aware, sir, that ever since living remembrance flood-tide has been gnawing and mumbling its way into this bay to the extent of three or four feet per annum? Forty inches, and forty inches, and forty inches corroding on and on: Watch it, sir, man and boy as I have these sixty years past and then make a century of it. Not to mention positive leaps and bounds. 'And now, think a moment of the floods and gales that fall upon us autumn and winter through and even in spring, when this valley is like a paradise to young eyes than any place on earth.

Walter de la Mare, All Hallows, 1927

Thanks a lot.

 

[Tarheel]

Yes! Indeed, you have it right.

 

[GoesStation]

The usual idiom is "by leaps and bounds," though Google's ngram viewer also finds a few instances with "in".

 

[Johnyxxx]

You are right, GoesStation, it was my mistake; my little favourite textbook called "1000 English idoms" says by leaps and bounds.