If you are the master of a great factory and all the machines go by your will -- when you come home, are you happy, restful, and peaceful? You may be the master of a whole army, or of a whole nation, or of many nations -- when you are at home, are you peaceful and happy? No. This shows us that another mastery is needed. One man may be the master of a whole army, and if he has a stroke of paralysis, all his mastership is gone, and he can do nothing. This shows us that this mastership is very passing. The mastery of the self is needed. It is not more difficult than the other. But as much will, as many years as a man gives to be master of a factory, he will never give to this. Because the results are much less tangible. A factory means so many pounds tomorrow. The results of the other are much subtler, much less perceptible.