1903 isotherm map with early explorer's routes is interesting.

I've looked a fair number of maps of Antarctica so when I point out how unique and interesting any one particular map is, you can be assured that my choice is based on some fair judgement. I'll study the following map more closely in coming weeks but I wanted to post it now for my readers. I noted that the easiest lines to follow are the winter and summer isotherm lines. Interestingly, in my view, those isotherm lines would be the ideal routes for an ship's expedition to take to prove 15K or 60K.