The arte of logick Plainely taught in the English tongue, according to the best approued authors. Very necessary for all students in any profession, how to defend any argument against all subtill sophisters, and cauelling schismatikes, and how to confute their false syllogismes, and captious arguments. By M. Blundevile.

Of Changed Proportion.

WHat is changed Proportion?

Changed Proportion is when the Foundations, and Termes of two like Proportions are answerable in proportion aswell amongst themselues, as one to another.

What meane you by these two words, Foundation and Termes?

The Foundation is that from whence the Comparison first proceedeth, as the Father, and the Terme, Bound or end is that whereunto the said Comparison is applyed, and endeth in the same, as the Sonne and therefore the Son is called the Terme, Bound or end: whereof wee haue spoken before in the Predi∣cament of Relation.

Giue Examples of reasoning from this place.

Looke as 8. is to 4. so is 12. to 6. (that is to say) in double proportion one to the other: Ergo, as 12. is to 8. so is 6. to 4. for each other containeth the other once and a halfe, which is called proportio sesquialtera. The manifest Demonstration wher∣of you may see in this Figure heere following.

[illustration]

Why is this Proportion said to be changed or transposed?

Because the order of numbers that are compared, is altered in the conclusion: for in the Antecedent the first is compared to the second, and the third to the fourth: but in the Con∣clusion the third is compared to the first, and the fourth to the second.