(Looking at Joe's great old photos reminded me that I had posted this scan on the Canadian Forum several years ago, and I went looking for it tonight. Below is the description I had written at the time. There was a second pic / close up but I don't know what happened to the file. The original book is still in the lobby of my bank)

While waiting to speak with a bank manager this morning I sat and browsed through a coffee table book they had on the origins of their bank. The attached photos were taken in Portsmouth, New Hampshire in the 1870's. The pieces atop the poles appear to look very similar to the House insulator which is written of in MacDougald's Volume 1, page 5. There is supposedly only one complete example known and it is in the Smithsonian.

The bank was located there in the 1840's. The time frame and geographic location seem to fit. What do you think?

(Note the crossarm nailed to the tree, probably some nice glass there, too)