If we attempt to do to much at once, we shall not do anything properly,
because He who begins many things, finishes but few.

In the old days before motor transport, when horses were in great demand,
blacksmiths were busy men. The ‘ _irons in the fire_ ‘ were for forging into
horseshoes, and if the blacksmith had a number of horses ready to be shoed, he
might try to save time by putting too many irons in the furnace, so that the
heat was insufficient to make them all red-hot.