There were no bubbles inthe tub of varnish. Every time I picked up the rag it made thousands of bubbles that didn't rise and pop. It was a rather cool morning (42F outside, a bit warmer in the garage). I think that made the varnish more viscous. I'll thin it down a bit tomorrow and warm up the varnish in a pan of hot water. I'll slow down the wiping.

Thank you all for your help.