Excerpt from Journal of the Franklin Institute of the State of Pennsylvania, 1830, Vol. 9: Devoted to the Mechanic Arts, Manufactures, General Science, and the Recording of American and Other Patented Inventions That tin being a softer metal and more easily abraded, the fric tion increases when a load is applied above 8 lbs. Per square inch, but remains nearly the same with the broad side as with the narrow side. Generally speaking, the friction is less with the broad side than with the narrow side. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.