Scientific American online has now been purchased by the University as part of a package from its new publisher, the Nature Publishing Group.
Previously online access was only via EBSCOhost Business Source Complete, a more business type database, which requires you to search specific words etc. to access the content.
Now that Scientific American is published by Nature it looks like any other online journal and so should me much easier and more interesting to search and download articles from. Access to the full text is available to the past 48 months' worth of content.
Full text online access to the journal content from 1846-1869 is also now available, as provided by Cornell University Library.
All of this content is accessible via ejournals@cambridge at: http://camsfx.hosted.exlibrisgroup.com/cambridge/az