Blog: Qu'est-ce que c'est que ca?
![questcequecestqueca 0](https://31.media.tumblr.com/b4ca6f64cba59d930fb3eb9c2356c19c/tumblr_n1y0bsjowK1qlpde9o1_500.jpg)
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original: https://questcequecestqueca.tumblr.com/post/79045280742
Protection against that dreaded disease Silicosis is assured underground workers with this new sand-blasting helmet developed by William P. Biggs, Safety Engineer of the Navy Department, 1936.