The alkyl alkoxy silanes and Silicon esters, a group to which methyl trimethoxy silane (MTMOS) belongs, are chemically stable and can penetrate deeply into stone the polymerization of MTMOS both by itself and in contact with powdered marble and silica involved monitoring the process visually and with infrared spectroscopy. Relative humidity played an important role in the process: the higher the relative humidity, the faster and more complete the polymerization (the lack of water at lower relative humidities does not allow the hydrolysis of methoxy groups to silanol to proceed to completion), but the greater the degree of crack formation. MTMOS has little chemical affinity for marble and appears to consolidate it by physically surrounding loose grains with a network of polymer rather than chemically bridging the grains. See also 21-1334 for entire proceedings. -- AATA