Imagine if these were aluminum, which was expensive in the 1870s...
(http://www.tms.org/pubs/journals/JOM/9511/Binczewski-9511.ht...)
Imagine if these were aluminum, which was expensive in the 1870s...
(http://www.tms.org/pubs/journals/JOM/9511/Binczewski-9511.ht...)