This collection consists primarily of a memorandum book kept by Philadelphia merchant Michael Bartholomew Mahony between 1879 and 1883. Mahony recorded observations on the weather, local and international news, household activity, financial transactions, and the deaths of friends, family members, and acquaintances. The collection also contains two photographs and a number of loose receipts, newspaper clippings, and other pieces of paper ephemera.

This weather diary kept by an unknown resident of Phildelphia, Pennsylvania, contains daily entries, June 1, 1836, to July 31, 1842, recording the temperature and wind direction along with brief comments on the weather. There are monthly rain measurements for 1825 through 1842 recorded "as per gauge kept at the Pennsylvania Hospital" as well as newsclippings documenthing especially severe weather events.