Well, there turned out to be a tiny, although visible, hole in the inner tube, so I thought I would patch it, but then I discovered that both my tubes of rubber cement had dried up. By the time I had put my spare tube in, however, that had a hole in it too. No comment. No, I did not use levers to put the casing on.
So, I took the tiny roll of DucTape I keep in my jersey pocket--about one foot wrapped around a short piece of drinking straw--and tried patching the hole in the original tube with that. I put two layers on, and for added good measure, I placed a piece of inner tube between the tube and the casing. This time the tube sprouted no additional holes after I replaced the casing. I pumped it up to more than it had been holding before, but not full pressure; I would estimate maybe 70 or 80 PSI; 60 at the very least. I heard no hissing, and it seemed to be holding air, so I set off home. At this rate I was not going to press my luck anymore, even though Conestogo and back is a very short ride--though further than I would want to walk back. (Oh, okay, the distance to my home was 9 kms).
I got home without further incident. When I went to change the entire front tyre later that evening, it still seemed to be holding as much air as it had when I had left Conestogo, although I never did think to measure it with a gauge.
So, now you can see, this entire story is an unpaid testimonial to The Power of DucTape.