I have found that sentence with a better spelling here (Note: The Littré anneau entry states: d’après Ménage, au XVIIe, on reprochait aux Parisiens leur prononciation agnau, qui est encore celle de quelques provinces) :

• le louage d’une bigorne, en quoy les cercles, lians et anneaux dudit canon ont été dressés et mis à point

In modern French, that might be something like:

• la location d’une enclume sur laquelle les cercles, liens et anneaux dudit canon ont été forgés et ajustés

and an English translation attempt:

• the rental of an anvil on which the said cannon circles, links and rings
  were forged and adjusted

Google translate gives from the original and modern versions:

• the hire of a horn , Wherein circles , rings and Lians said barrel have been prepared and placed at the point

• renting an anvil on which the circles , links and said barrel rings were forged and adjusted