It was probably water glass, or sodium silicate.
You are right. I was looking it up as you posted. Thanks. So my memory is still good!!!! That’s good to know.
“”Waterglass is another name for sodium silicate, a chemical compound that has many uses. Waterglass has been used for egg preservation since the turn of the last century and is one of the most successful preservation methods available. When mixed with water, waterglass forms a gelatinous substance in which eggs are completely immersed and stored in a crock in a dark, cool location. Waterglass can preserve eggs for five months or more without refrigeration and can be reused for subsequent batches of eggs. Waterglass works like lard in sealing up the pores of the egg and preventing air and bacteria from entering. It is easy to store and can be made up into solution as needed.””