Poppy seed or sesame seed -(optional) * (Water which peeled potatos have cooked in. Plain water may be used, but it's not as good.) Sift together dry ingredients. Soften yeast in 1/3 of potato water. Add to flour. Add oil to remaining potato water and stir into the flour mixture. Add eggs and stir briskly to form a ball of dough. Knead on a lightly floured board for 10 minutes. (This MUST be a firm dough) Add more flour if necessary. Return to the bowl--smooth side up. Cover with a towel (tea etc) and let rise at room temperature until the dough rises to the top of the bowl. Knead again on a lightly floured board until smooth and elastic (as for rolls). Pinch off pieces of dough and roll between the palms of the hands to form ropes about 6 inches long and 3/4 inches wide. Pinch the ends together firmly to make a doughnut shape. Add sugar to boiling water. Drop bagels into water one at a time. As they come to the surface, turn them over. Boil 1 minute longer on the second side. Place on a greased cookie sheet and bake at 450 F. until the crust is golden brown and crisp--10 to 15 minutes. Bagels may be sprinkled with poppy seed or sesame seed before baking if you like.