You have seen a few of the posts already on the Guest Blog. They have now been moved to the new blog, where Mary Karmelek will bring you joy roughly twice a week. From the About page:
In 1845 Scientific American magazine made its debut on newsstands and has continued to be published ever since. Now, Nature Publishing Group and Scientific American are working to digitize all past issues of the magazine. Mary Karmelek is in charge of checking over each issue, and in the process she uncovers fascinating, captivating and humorous material buried in the yellowed pages of our past. In this blog she shares the highlights of her discoveries. Additional archival material appears every month in our 50, 100 and 150 Years Ago column.