I've checked the census for 1851, 1871 and 1881, and this is all that I could come up with:

In 1851, there was a Henry Douglass (age 15) in Ancaster Township (Twp # 390, p.151, reel # C11758):
http://data2.collectionscanada.ca/1851_pdf/e095/e002373464.p...

(There's no Henry Douglas (one 's'); the personal census for some townships is missing, or incomplete, though)

In 1871, no mention of a Henry Douglass, but there are four Henry Douglas, although none in the Hamilton area, and none appear to be the Henry Douglass from 1851.

In 1881, according to Familysearch.org, we possibly have your Henry Douglass in Owen Sound, Ontario: Henry A. Douglas (one 's') born 1845, occupation merchant, married to Alice E. Douglas.

You may in the end want to consider contacting the Hamilton Branch of the Ontario Genealogical Society:
http://www.hwcn.org/link/HBOGS/Researchservices.html

I could check the Spectator for you, but it may be a while before I go to the library to do more research.

Hope this helps,
Ken