2 National Chair Co chairs.

I have two identical chairs that have markings under the wooden seat that say 640, 35 of 54 and a capital D followed by what could be ec for December or ean for Dean. See photo. 

The tallest point is 35 1/2 "  and the back is 13 1/2 " wide. They are in good condition.

I don't know anything about them except the man i bought them from said they were old. He was a visiting Russian scientist who was selling everything to move back to Moscow. I paid very little, maybe $15 for the pair.

Fair