The third elementary type of relationship between government and banking system, already referred to at the opening of this chapter, was seen in the fact that the government is itself a large depositor, and is therefore able to exercise over all banks that kind of control which customers always exercise, whether in public or in private life, over the concerns with which they trade. The government of the United States is to-day the greatest business enterprise and the largest depositor in the country. Much the same is true of all modern nations, and it is everywhere a fact that the volume of taxation and other revenue flowing into the public coffers, and usually flowing out quite as promptly, is the largest single stream of wealth within the national borders. The question during the past hundred years has always been urgent, how this wealth should be handled and what use should be made of it. Even though it be true that the government has no large accumulation of funds that it does not need at any given time, it is a fact that there is always in the public purse a great quantity of fluid funds which are being turned in one direction or another.