3. The coming to maturity of American bonds held abroad is another influencing factor closely kept track of by dealers in exchange. So extensive is the total foreign investment in American bonds that issues are coming due all the time. Where some especially large issue runs off without being funded with new bonds, demand for exchange often becomes very strong. Especially is this the case with the short-term issues of the railroads and most especially with New York City revenue warrants which have become so exceedingly popular a form of investment among the foreign bankers. In spite of its mammoth debt, New York City is continually putting out revenue warrants, the operation amounting, in fact, to the issue of its notes. Of late years Paris bankers, especially, have found the discounting of these "notes" a profitable operation and have at times taken them in big blocks. Whenever one of these blocks of revenue warrants matures and has to be paid off, the exchange market is likely to be strongly affected. Accumulation of exchange in preparation is likely to be carried on for some weeks ahead, but even at that the resulting steady demand for bills often exerts a decidedly stimulating influence. Experienced exchange managers know at all times just what short-term issues are coming due, about what proportion of the bonds or notes have found their way to the other side, just how far ahead the exchange is likely to be accumulated. Repayment operations of this kind are often almost a dominant, though usually temporary, influence on the price of exchange. 4. Low money rates are the fourth great factor influencing foreign exchange upward. Whenever money is cheap at any given center, and borrowers are bidding only low rates for its use, lenders seek a more profitable field for the employment of their capital. It has come about during the past few years that so far as the operation of loaning money is concerned, the whole financial world is one great market, New York bankers nowadays loaning out their money in London with the same facility with which they used to loan it out in Boston or Philadelphia. So close have become the financial relationships between leading banking houses in New York and London that the slightest opportunity for profitable loaning operations is immediately availed of.