This section is from the book "Many Ways For Cooking Eggs", by Sarah Tyson Heston Rorer. Also available from Amazon: Many Ways For Cooking Eggs.
To preserve eggs it is only necessary to close the pores of the shells. This may be done by dipping them in melted paraffine, or packing them in salt, small ends down; or pack them in a keg and cover them with brine; or pack them in a keg, small ends down and cover them with lime water; this not only protects them from the air, but acts as a germicide.
Eggs should not be packed for winter use later than the middle of May or earlier than the first of April. Where large quantities of the yolks are used, the whites may be evaporated and kept in glass bottles or jars. Spread them out on a stoneware or granite plate and allow them to evaporate at the mouth of a cool oven. When the mixture is perfectly dry, put it away. This powder is capable of taking up the same amount of water that has been evaporated from it, and may then be used the same as fresh whites.