340 year archive available free on the web through until mid-November. So if you want to see some historically important scientific papers without paying, do so soon.
I liked this bit about Benjamin Franklin that ran in the Philosophical Transactions from the Society in either 1751 or 1752. The letter s is often replaced with an f. The topic is also pretty strange. So little was known about electricity in the middle of the 18th century that it was a novel idea that chickens and turkey could be killed through electrocution. The big turkey held up for a while, but when Franklin increased the juice, he failed to recover.
Faraday, Newton, Watson and Crick, and Hawking have all been published by the Royal Society. Take a look.