Money
It has such an inherent power to run itself clear of taint that human ingenuity cannot devise the means of making it work permanent mischief, any more than means can be found of torturing people beyond what they can bear. Even if a man founds a College of Technical Instruction, the chances are ten to one that no one will be taught anything and that it will have been practically left to a number of excellent professors who will know very well what to do with it.