Section plan of area Π in 1935+ ... Heliotype of PD 260 with notebook references fn. Π, ΜΣ, Λ, etc. stored here. f Fragile Gauzed Graph Paper Drafting Ink
Pencil ... 1935 ... Heliotype of PD 260 with notebook references fn. Π, ΜΣ, Λ, etc. stored here.