Around 1861, Holmes devised what would later be known as the “American” type of stereoscope—an inexpensive handheld device with slots to hold the stereographs at different distances and a hooded eyepiece overall, distinct from the box-shaped stereoscopes then in common use. Joseph L. Bates of Boston crafted the initial model for Holmes and then made his own improvements on the design and patented it in 1867. Holmes had no interest in patenting or marketing the stereoscope but said of Bates, “I was very glad to have somebody get profit and pleasure from my contrivance, and made him quite welcome to whatever there was to be gained by its manufacture…. From his establishment have come certain improvements of much value, particularly the sliding arrangement for adjusting the focus, in place of the original slots, or narrow grooves, and the method of holding the pictures.” The Wheeler and Bazin-type folding stereoscope, with its own sliding focus, was patented in 1863. The stereographic view displayed here belonged to Holmes who mentions it in a letter to Mrs. Asa Gray, in 1871: “I have stereographs of the Boston Elm, before its present condition of decadence, and one of the Washington Elm, the last a fair specimen of the tree….” Stereographic photographs of the Old Elm in Boston Common, owned by Oliver Wendell Holmes (1809-1894)