Identified through information published in John Ferguson's Walter Holtkamp: American Organ Builder (DMA treatise, Eastman School of Music, 1976). Although neither Votteler-Holtkamp-Sparling nor their successor Holtkamp Organ Co. assigned Opus numbers to their instruments, this organ was identified in factory documents as Job number 1631. That number appears here as the Opus number of this instrument. This is the Chancel Organ; Job no. 1630 applied to the Gallery organ.