Take the weight of four fresh eggs in sugar, and half the weight in flour, mixing with the latter half a teaspoonful of cream of tartar, and quarter teaspoonful of soda very thoroughly, or the eclairs will not be light. Beat the yolks of the eggs until light, add slowly the sugar, as you do for sponge cake, having it just as light. Alternate the beaten whites of the eggs with the flour, and bake in pans having compartments, dropping a spoonful of butter in each, or in a paperlined and well-buttered pan, making the cakes is nearly the size of lady-fingers as possible. The oven should be quick, and when done take out, place two together, allow them to cool, and cover with the chocolate.