A mechanic of this city has constructed and set in motion a steam engine on the novel but obvious plan of working the “ inlet and ou,tlet valves “ by the direct' action of steam, instead of deriving the requisite power from the main agency of a train of working gear, as has been the practice hitherto. The valve- openings are placed in the ends of the cylinder—the valves are those most approved (puppets) —and the working is easy, precise, and rapid to a degree in any other mode of working impossible. In the old modes of working the valves, their motion is continued d urin g the passage of the main piston through the length ot the cylinder ; in the new mode of working, with the disadvantages incident to their first construction, “ the inlet and outlet valves “ are fully opened in one twenty- fifth part of the passage of the main, pistons through the length of the cylinder, and that so easy as not to be heard when working to an hundred and fifty revolutions per minute. The effect of the new mode of working the valves is to greatly reduce the bulk, weight, and cost of the engine, which is rendered more simple, effective, and durable, and the obstacles to the working of locomotives on common roads are in great part removed.— [New York Tribune. [So far as the valve openings are concerned, by being situated in the end of the cylinder, this is nothing new, and we can understand it, but how the valves (puppets) are to be operated by the direct action of the steam, instead of its secondary action, is more than we can comprehend. Some rotary engines work by the re-action of steam like a turbine water wheel; they do not require common or uncommon valves. With respect to the cutting off, plenty of our engines can do this at any put of the stroke. How in the name of all that is sensible in mechanics this engine removes the obstacles to the working of locomotives on common roads, h more than w can imagine, unless the roads themselves are' removed. The obstacles are not in the engine—th e locomotive—but in the very nature of the roads, and the obstructions to free travel on every public road, which are all happily obviated by the railroad. There have been engines in operation in this city for years, which have no valve rods, nor puppet nor slide valves—no valves at all—but simply ports, which the cylinder opens and closes itself. To talk about working . 1o«omotives on common roads when we have railroads, is just about as bright, consistent, and sensible an idea as it would be to advocate lighting up our city with the old oil lamps in place of gas light. Before railroads were in use, the application of steam to common roads was a sensible idea, but even then, after repeated trials in England, and after more than thirty of such engines had been built and tried, they failed to produce any satisfactory results, and When lo comotion on railroads was introduced, they all died a natural death. There are some people, h j ever,, who do not kno'v about these things, and whose experience in practical mechanics is so small as often to lead them to impose upon themselves thus a patent was taken out last year in Eng. land, by a distinguished foreigner, for a horsepower for railroad s, which is just as sensible an idea as steam coaches for common roads.