Here are BK's picks from that same estate sale where I got those old National Geographic magazines posted last week. He loves old math and science books and these in particular are actually antique since they were published more than 100 years ago. This one by Milne was published in 1892.
Funny to think that 100 years ago they thought they were revolutionizing methods of teaching math to be more accessible and practical. Curriculum has come a long way since then!