Ready References
Beginner's Corner, Jul. 1939
Binoculars: Halfway to a Telescope
Choosing Binoculars for Astronomy
Celebrated Variable Stars
Control Instrument Applications
Molding and Casting
Fossil Succession
Ready References 
Beginner's Corner, Jul. 1939 Binoculars: Halfway to a Telescope Choosing Binoculars for Astronomy 
Celebrated Variable Stars 
Control Instrument Applications Molding and Casting Fossil Succession