"A new, three-manual chapel organ by Hilborne L. Roosevelt was inaugurated in 1882; reportedly tuned to the pitch of a Steinway piano so the two could be played together, it burned in a 1918 fire in Main Building." -- information from Vassar Chronology records via Laurence Libin

Organ dedicated March 17, 1882, as reported in the Poughkeepsie Eagle-News, 18 Mar 1882, Sat · Page 3: "There are three manuals and twenty-five speaking stops, as shown by the schedule below, all having been selected by Dr. Ritter with the intention of producing the best effect..." The published specification lists three ranks "Blank for.." and [mistakenly] lists pipe counts for each of these. The pipe count given on this record reflects the prepared for stops not being installed. See docs tab for article.

"Performances in the Chapel by Professor of Music Frederic Ritter and college organist Charlotte Finch ’72 and a surprise recital by Walter Damrosch, son of the founder of the New York Symphony Society, highlighted the dedication of a new organ. The gift to the college of Mrs. Bertha Adelé Dean, the wife of Trustee John A. Deane, the instrument was made by the New York City firm of inventor and organ pioneer Hilborne L. Roosevelt. Tuned to the pitch of a Steinway piano, "so that," The Vassar Miscellany reported, "the two instruments can be used together," the organ "though not the largest instrument made by the builder...is, in every detail, his best work."

Visiting the college for this occasion along with members of the New York Philharmonic Club and his father, Leopold Damrosch, 22 year-old Walter Damrosch enchanted his audience with his impromptu recital. "Like wild fire," said The Miscellany, "the news ran through the corridors that Mr. Damrosh [sic] would play in the chapel at eight, and when the hour arrived, nearly every inmate of the college was found seated in the chapel ready to enjoy. Nor was any one...disappointed. For nearly two hours we were charmed by the little impromptu concert.... He delighted us, both upon the organ and the piano." -- from a Documentary chronicle of Vassar College, https://www.vassar.edu/chronology/records/1882/1882-03-17-new-organ.html, accecssed 2021-01-31

The organ is mentioned on June 15, 1882 in a report on Commencement in the Poughkeepsie Eagle News