Julia Child's Country Bread

This recipe is taken from Julia Child's Baking with Julia cookbook.  You create a sponge which consists of flour, warm water and yeast.  The interesting aspect of this particular sponge is that it consists of 3 different flours:  Unbleached All Purpose, Whole Wheat and Rye.  Last night, I mixed the 3 flours, warm water and yeast and covered the bowl with Saran wrap and a dry dish towel.  I left it on my kitchen counter.  This morning the sponge was very much alive and well!  This will be added to the ingredients that make the final dough.  The final dough will have two "risings" before it is finally baked.   I am off to the kitchen.  Let's see what happens!