Got ahold of some negatives from the 1930's and 1940's. How do I view them?

I got ahold of some negatives from the 1940s and 1930s thanks to a generous person. Now I don't know how to view them because I'm a bit new to scanning negatives... Only know how to view 35mm, which these are not.Also one set of negatives looked rather greasy and when I wiped it, white powder got on my fingers, does anyone know what this is?Thank you!!!!! via /r/photography http://bit.ly/2H8zTUo