Many of the photographs he took were of mountains which had not been previously recorded and so have historical as well as artistic significance; for example by recording the retreat of glaciers in the Rwenzori mountains in Central Africa.
Řada jeho fotografií hor, které pořídil, nebyly do té doby ještě zaznamenány, a tak mají kromě umělecké také historickou hodnotu, například záznam ústup ledovců v pohoří Ruwenzori ve střední Africe.