This invention consists, briefly, in the injection of a certain amount of atmospheric air into the steam cylinder, and the admixture thereof with the steam. A saving of 33 per cent in the fuel has been claimed for the improvement. It is the invention of fm. Mt. Storm, of this city. Sundry experiments, it is said, have at times exhibited the above gain, while others have shown no advantage to arise from the improvement. P. McManus, of Troy, N. Y., a part owner of the patent, writes us that he has lately put in operation at that place a 7-horse horizontal engine, with the Cloud improvement attached, which works successfully. It is said to have run ty days at a consumption of one tun of coal. But when the air was shut off, and steam alone used, the engine only ran 2A days on the same amount of coal, and performed less work at that. Mr. McManus claims to have discovered a remedy for the irregularities that have attended former experiments. If the data is correctly stated, the above trial exhibits a nominal saving equal to 50 per cent in fuel. This seems too good to be true. We understand that the engine can be seen in operation at the Phcenix Works, 543 River street, Troy. Can't some of the scientific Trojans look into this matter, and report upon it ? Where is Professor Wells?