sentences:  The organ was later rebuilt and enlarged first by Niels Johnson (1889), the Kimball company of Chicago (1901), the Austin company of Hartford (1915, 1926 & 1937) and finally by the Aeolian-Skinner organ company of Boston (1948).The organ today is largely the result of the personal involvement of noted Anglo-American organ builder G. Donald Harrison, president of the Aeolian-Skinner organ firm when the tabernacle organ was installed.His collaboration with legendary tabernacle organist Alexander Schreiner produced this masterwork of American eclectic organ building.