Google books is a wonderful resource, but a bit disorganised. It has several copies of some book, lots of items where there is only one volume of a multi-volume work, and plenty of cases where the description has been attached to the wrong book! As the scanning is ongoing, I hope that more gems will be available in time.

Microsoft did try to set up in competition, but abandoned its own version earlier this year.

They have copies listed there of Kidson, Bronson, etc, but none of them browsable as far as I can see. Several editions of Pills to Purge Melancholy are there and some are fully viewable:

Pills to purge melancholy

You can also find some jokes from 1850 which are still current!

Repository of wit and humor