The natural philosophers in power believe that Dr. Franklin has invented a machine of the size of a toothpick case, and materials that would reduce St. Paul's to a handful of ashes.
The rumor is sarcastically delivered, in reference to one John the Painter's plan to burn down the Bank of England, "for stone and gold are wonderfully combustible." But, Franklin, who did devise a simple but invaluable means to conduit lightning, was often reputed to have mastered powers and technologies long before their time had come. (See Marguerite GĂ©rard's etching To the Genius of Franklin) He was also said to have designed a means of wielding sunlight into, essentially, a death beam with which to repel the British navy.
These rumors roughly describe technologies that were in fact designed by Nikola Tesla over one hundred years later. The designs, particularly Tesla's "death ray," were said to have been seized by the U.S. government upon his death and developed in black budget weapons programs.
As for their destructive potential, consider Tesla's self-report of testing his alarm clock sized mechanical oscillator (only a little bigger than Franklin's reputed toothpick case sized device) upon a steel construction site in 1898, as told in Margaret Cheney's Tesla: Man Out of Time...
...he put the little oscillator in his coat pocket. Finding a half-built steel building in the Wall Street district, 10 stories high with nothing up but the steelwork, he clamped the oscillator to one of the beams.
"In a few minutes I could feel the beam trembling. Gradually the trembling increased in intensity and extended throughout the whole great mass of steel. Finally the structure began to creak and weave, and the steelworkers came to the ground panic-stricken, believing that there had been an earthquake. Before anything serious happened, I took off the oscillator, put it in my pocket, and went away. But if I had kept on 10 minutes more, I could have laid that building flat in the street. And with the same oscillator I could drop Brooklyn Bridge in less than an hour."
Then, some 103 years later, there were those two 110 story completed structures, nearby in Lower Manhattan, that were, in professor Judy Wood's terminology, "dustified" into a blizzard of ashes by what, we cannot say with certainty. However, some eyewitness (or better, "bone-witness") accounts of rumblings immediately before the felling of the towers might suggest that something like the reputed Franklin device, or Tesla's "earthquake machine," was deployed...Pg. 5 of Bradley Mann:
Shortly before the first tower came down I
remember feeling the ground shaking. I heard
a terrible noise and then debris started
flying everywhere.
Pg. 7 of Louis Cook:
Okay. I start going across this
pedestrian bridge. I'm the only one on this
bridge. I'm walking across it, and then I just
remember feeling a rumble and hearing this
rumbling sound that was really intense. It
actually shook my bones.
Pg. 11 of Paul Curran:
...all of a sudden the ground
just started shaking. It felt like a train was
running under my feet.
...The next thing we know, we look up and
the tower is collapsing, it's coming down.
Pg. 10 of Karin Deshore:
...a sound came from somewhere that I never
heard before...It was the worst sound of a
rolling sound, not a thunder. I can't explain it,
what it was. All I know is -- and a force
started to come hit me in my back. I
can't explain it...