In his recent address to the British Association for the Advancement of Science Sir William Ramsay dealt with the self-disintegration of atoms, especially radium atoms, and then went on:
This leads to the speculation whether, if elements are capable of disintegration, the world may not have at its disposal a hitherto unsuspected source of energy. If radium were to evolve its stored-up energy at the same rate that gun-cotton does, we should have an undreamed of explosive; could we control the rate we should have a useful and potent source of energy.... If some form of catalyser [promotor of atomic change] could be discovered which would usefully increase their [such elements as radium] almost inconceivably slow rate of change, then it is not too much to say that the whole future of our race would be altered.
A Scientific American writer follows on naturally:
Iodide of nitrogen, a black powder, is one of the most dangerous of all explosives. When dry, the slightest touch will often cause it to explode with great violence. There appears to be a certain rate of vibration which this compound cannot resist. Some of it in the damp state was rubbed on the strings of a bass viol. It is known that the strings of such an instrument will vibrate when those of a similar instrument, having an equal tension, are played upon. In the present case, after the explosive had become thoroughly dry upon the strings, another bass viol was brought near and its strings sounded. At a certain note the iodide exploded. It was found that the explosion occurred only when a rate of vibration of sixty per second was communicated to the prepared strings. The note G caused an explosion while E had no effect.
The writer goes on to state that damage to stone and brick walls has been traced to long continued violin playing.
It follows, of course, that there must have been continuous playing for years to cause the loosening of masonry or to make iron brittle, but it will do so in time.
The point of interest is the special rate of vibration required to set free the energy locked up in the iodide of nitrogen. It was intra-molecular energy. Sir William Ramsay was referring to the far greater stores of intra-atomic energy, energy within the atoms, holding each one together. The other ties them one to another within the molecule, i. e., holds the molecule together.
But may not the atom too respond to some special rate of vibration producible by sound, lying far among the upper harmonics of any audible tone? This at any rate was Keeley's statement and claim. The causes of his equally unquestionable successes and failure may be worth looking into once more now that a certain high temperature surrounding the subject has died down. Sound may be Sir William Ramsay's "catalyser."