My collection of pulleys. Interestingly, the word "pulley" has nothing to do with the action of pulling, but apparently derives originally from the Greek word for "pivot" or "axis."
Below, some uses:
|Wilbur L. Beauchamp, Gertrude Crampton and William S. Gray. |
How Do We Know? Basic Studies in Science, Book C.
Toronto: W.J. Gage & Co., Ltd., 1957.