Dutch reckoning

As if all Light of Reasoning were so shut up in Clavius his Brain, that because he does not see, the rest of Mankind must be blind; and what is that way of Reasoning that he betakes himself to, but by huddling the Principles of Geometry into Confusion, without order of method of Reasoning, to make a Conclusion, like a Dutch Reckoning of Allem-al?

1 March 1625 in the Dutch reckoning was, in the English reckoning of the time, 19 February 1624.