"The Presbyterian clergy are loudest, the most intolerant of all sects, the most tyrannical and ambitious; ready at the word of the lawgiver, if such a word could be now obtained, to put the torch to the pile, and to rekindle in this virgin hemisphere, the flames in which their oracle Calvin consumed the poor Servetus, because he could not find in his Euclid the proposition which has demonstrated that three are one and one is three, nor subscribe to that of Calvin, that magistrates have a right to exterminate all heretics to Calvinistic Creed. They want to re-establish, by law, that holy inquisition, which they can only infuse into public opinion."
In the first quote he is speaking of Michael Servetus. Calvin was involved in his extermination. Here are some quotes relating to the incident."When we shall have done away with the incomprehensible jargon of the Trinitarian arithmetic, that three are one, and one is three; when we shall have knocked down the artificial scaffolding, reared to mask from view the simple structure of Jesus; when, in short, we shall have unlearned everything which has been taught since his day, and got back to the pure and simple doctrines he inculcated, we shall then be truly and worthily his disciplines."