Lefax Facts Highway & Surveying Tables

The information available in the form of a Lefax binder, many years ago was so amazing and interesting. The example I have here is a personal sized binder Leaf & facts for Highway & Surveying Tables, is crammed full of calculations for the road and bridge building engineer.
The original owner L D Purdin used this during the 1940's and the binder still contains the pencil notes made when it was in use. Remarkably the binder is still in one piece. I have taken a few pictures so that you can get an idea of the amount of information contained within the Lefax.