drown the miller

Originally drown the miller's thumb, meaning to go over the specified mark.

drown the miller (third-person singular simple present drowns the miller, present participle drowning the miller, simple past and past participle drowned the miller)

1. (obsolete, idiomatic, slang) To put too much water in something; overdilute.
   • 1821, The Economist, page 241:

     […] I tell my Bowl Friends, that our ministers have spoilt the punch. Sometimes they give us too much spirit, as when they display a vigour beyond the law; and sometimes, as we say, they drown the Miller, and make sad insipid stuff of it; again they sting our throats with acid; but it is not once in a century that we have cause to complain of an excess of sugar.

• John Camden Hotten (1873) The Slang Dictionary