Declaration of the National Anti-Slavery Convention was written by William Lloyd Garrison for the formation of the American Anti-Slavery Society in December 1833. It was reprinted in The Liberator on December 14, 1833. It is now available in the Public Domain.
You can also use the Optimized PDF option to crank the size down in very targeted ways. Given the big before/after shift, the culprit is probably the image you're embedding. Try exporting that file in various formats (PDF, jpg, png) and then import it.
Automatically scale to fit paper. Acrobat can size the pages of a PDF to fit the selected paper size. Choose File > Print. From the Page Scaling pop-up menu, select one of the following options: Fit To Printable Area Scales small pages up and large pages down to fit the paper.