it is conceivable that at a certain temperature calcium carbide might be capable of withdrawing the water of hydration from the molecule of slaked lime, converting the latter into quicklime, and liberating one molecule of acetylene, thus-- (3) CaC_2 + Ca_2(OH) = C_2H_2 + 2CaO. It has been proved that a reaction of this character does occur, the temperature necessary to determine it being given by Lewes as from 420° to 430° C., which is not much more than half that which he found in a generator having carbide in excess, albeit one of extremely bad design. Treating this reaction in the manner previously adopted, the thermo- chemical phenomena of equation (3) are: _Heat liberated._ | _Heat liberated._ | Formation of 2CaO 290.0 | Formation of acetylene 58.1 | Decomposition of Ca(OH)_2 [1] 229.1 | Decomposition of carbide 3.9 Balance 1.1 | ______ | _____ | 291.1 | 291.1 [1 Footnote: Into its elements, Ca, O_2, and H_2; _cf._ footnote, p: 31.] Or, since the calcium hydroxide is only dehydrated without being entirely decomposed, and only one molecule of water is broken up, it may be written: Formation of CaO 145.0 | Formation of acetylene 58.1 | Decomposition of Ca(OH)_2 15.1 | Decomposition of water 69.0 Balance 1.1 | Decomposition of carbide 3.9 _____ | _____ | 146.1 | 146.1