Autumn--F. G. Irwin visits Eliphas Levi in Paris.
October 14--Helena P. Blavatsky meets Colonel Henry S. Olcott for the first time at Chittenden, Vermont. They start to correspond with one another; later, they will join forces to further the goals of Theosophy.
November--H. P. Blavatsky moves to Philadelphia.
December--S. N., Thomas Vaughan (F. G. Irwin) writes The Star Rising in the Est, or a Brilliant Light Revealed unto all Men. According to Darcy Kuntz, "It has similar initiation ceremonies as those contained in the Golden Dawn Cipher Manuscript."
Important historical note: Colonel H. S. Olcott will lose his diaries for the years 1874 to 1877. This makes his accounts of the events of these years less than one hundred percent reliable as recounted in Old Diary Leaves. The missing years are those in which Blavatsky writes Isis Unveiled.
In mundane history:
First impressionist exhibition takes place in Paris. The term "impressionism" comes from the title, "Impression: Sunrise," a painting by Monet.
H. Solomon introduces pressure-cooking methods for the canning of food in the United States.
The first American zoo is established in Philadelphia.