Heading punctuation and formatting, which varied in the original, has been standardized. Illustrations on P. 63 (Printer), 73 (Type-founder), and 81 (Paper-maker) have no captions in the original. P. 66, "Durandi Ralionale divinorum officiorum" in the original is the official title in several sources. Retained "Ralionale" spelling. Changes not covered by notes above were: P. 10, "now became clefs"; original reads "clifs." P. 159, "convex drawing-knife"; original reads "onvex." End of Project Gutenberg's Popular Technology; Volume 2, by Edward Hazen