MECHANICAL INVENTION, to adapt steam to the heavy resistances of canal boats, is therefore the first and greatest necessity of canals. A second necessity will be AUXILIARY AND CO-OPERATIVE POWER AT THE LOCKS AND SHORT LEVELS. These must be local, and may be by stationary steam-power, by water-power from the upper levels, or by horses. Thus, there would be only one detention of a tug through all the sixteen locks from West Troy to Cohoes--only one wherever there are two or more locks near each other, and at all locks there must be an independent local power to handle all boats. In this way tugs will lose less time between Buffalo and Albany than horse-boats do in changing teams from boat to tow-path every six hours. Following these necessities, new rules, regulations and customs will be established, protecting the rights and equities of all. * * * * * A third necessity will be a CENTRALIZED MANAGEMENT, or control of all tugs, train-movements, and local powers at short levels and locks. This is essential to a harmony of movements, to a proper distribution of motors, and to a proper adaptation to all the ebbs and flows of trade. This is just as essential for the tugs of a canal as for the locomotives of a railway. Provided the control of steam shall be held, _upon the merits of some invention_, protected by Letters Patent from the General Government; then the owners thereof might establish a centralized management to meet the merits, demands and exigencies of the case. They could enforce a harmony of interests between all trains and a harmony of police regulations, and they could enforce a consolidation of effort and co-operation to meet any exigency, just as a railway company can consolidate and develop its efforts upon any necessitous occasion. * * * * * In the nature of the case, these three necessities, when accomplished, will give to steam _the universal movement of boats_. First.--Because it becomes a cheap motor in regard to which horses can hold no competitive claim. This is seen from the fact that when steam can only utilize from eight to twelve per cent. of its power, as under the two eras of steam, the two best steamers--the _S. B. Ruggles_ and _City of Buffalo_--lived five years in competition with horses, nothing since has exceeded their economies or capabilities; but give the steam they used a utility of thirty to fifty per cent., or over three times its present capabilities, and no team can be supported in competition. * * * * * Second.--Because it possesses the economies of concentrated power. Horse-power must be diffused into small and limited qualities to be economical. The cost of double, treble, or quadruple teams, to increase speed or reduce time, swells the cost of transportation almost in like ratio, and would eat largely into the value of cargoes.