Love this ad from Catalina Swimsuits from 1939.
"Ann Sheridan, Warner Brothers star selects this seasons most sensational swimsuit. A featherweight puckerette with hourglass waist and plain top, made of transparent 'oilsilk,' fully lined. Not ordinary oil silk but Endurette pure silk...waterproof processed to withstand stains and sun tan oils. Endurette oil silk is lustrous, odorless; keeps soft and silken! Complete the combination with headed coat or plain coat of the same material, to protect you against wind and sun, or pajamas to slip on over wet suit. Colors: apricot, blue, red and green."
I would love to see this and wonder if it survived the elements as claimed. But the transparency of the silk pajamas and cover up are something special don't you think?