sation of the 3'79 feet of stearn, or that which I which may be produced by the expansion of the high pressure steam. lUotion oC en tting Tools. It is commonly remarked among mechanics that a cutting-tool, being put in motion and applied to another object, has a greater efiect, in proportion to the power applied, than if the object to be operated on be put in motion and forced against the tool, while the latter PJlilosophy oC Water. is fi rmly fixed stationary; and, as an instance It is a

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... s fact that notwithstanding the of this, it is averred that if an axe be placed pm'fer of water to quench fire, and the general on the ground, with the edge upward, and be application thereof for that purpose, its com-struck while in that position by the edge of ponent parts, when simply mixed together ano ther equal axe, the edge of the fi rst will be without chemical combination, constitute the indented by the concussion much deeper than mo�t combustible and violently explosive com-that of the descending axle. If this be a fact, pound that is generally known. Itis composed we know of no rational theory in support of of oxygen and hydrogen in the proportion of 35 it, although not fully prepared to deny it; be ta 15. It is readily decomposed by chemica l ing aware that various kinds of cutting tools process, and reduced to a highly elastic gase-have a very different effect under different de ous state. The most ready method of produc-grees of velocity. It is well known that in ing the hydrogen gas, is to put a quantity of cutting, hewing, planing or splitting timber in zinc or iron filings into sulphuric acid diluted general, the more rapidly the tool is made to with twice its volume of water. The oxygen move, the more effectually and smoothly the of the water rapidly combines with the metal, work is accomplished, especially where the thus liberating the hydrogen whic' h ascends in direction of the grain of the wood is unfavora the form of gas, producing violent ebullition. ble; while, on the other hand, the fact is esta By placing this compound in a glass bottle or blished by modern practice, that in planing or flask, the gas may be collected either by attach-cutting cold iron,-either cast or maleable, ing a collapsed bladder to the neck of the bottle, a tool moving with a slow, but strong, steady or by conducting the gas through a small and permanent motion, will cut more smoothly, pipe to the interior of another bottle, fi lled and be more effective in its operation, than with water and placed in an inverted position, when driven by the concussion of a hammer;