Canal. It brought into the market lands and produce which before had been worthless, and was a great blessing to all concerned. There can be no doubt that the building of the Erie Canal was the wisest and most far-seeing enterprise of the age. It has left a permanent and indelible mark upon the face of the republic of the United States in the great communities it has directly assisted to build up at the West, and in the populous metropolis it created at the mouth of the Hudson River. None of the canals which have been built to compete with it have yet succeeded in regaining for their States what was lost to them when the Erie Canal went into operation. This water route is still the most important artificial one of its class in the country, and is only equaled by the Welland Canal in Canada, which is its closest rival. Now that it is free, it will retain its position as the most popular water route to the sea from the great West. The Mississippi River will divert from it all the trade flowing to South America and Mexico; but for the northwest it will be the chief water highway to the ocean. * * * * * COTTRAU'S LOCOMOTIVE FOR ASCENDING STEEP GRADES. We borrow, from our contemporary _La Nature_, the annexed figure, illustrating an ingenious type of locomotive designed for equally efficient use on both level surfaces and heavy grades. [Illustration: COTTRAU'S LOCOMOTIVE FOR ASCENDING STEEP GRADES.] As well known, all the engines employed on level roads are provided with large driving wheels, which, although they have a comparatively feeble tractive power, afford a high speed, while, on the contrary, those that are used for ascending heavy grades have small wheels that move slowly, but possess, as an offset, a tractive power that enables them to overcome the resistances of gravity. M. Cottrau's engine possesses the qualities of both these types, since it is provided with wheels of large and small diameter, that may be used at will. These two sets of wheels, as may be seen from the figure, are arranged on the same driving axle. The large wheels are held apart the width of the ordinary track, while the small wheels are placed internally, or as in the case represented in the figure, externally. These two sets of wheels, being fixed solidly to the same axle, revolve together.