Edison bi-polar dynamo, capacity sixty 10-candlepower lamps. Installed on S.S. Columbia in 1880.

Note written below image says that it is too early to be a Z-type dynamo as listed on the original photo caption. The note, written by Charles L. Clarke, one of Edison's long-time assistants, reads: "THis is not a "Z" dynamo, which had an iron base, and were first built very early in 1881. The statement that it (one of four) was installed on the S.S. Columbia is correct. Between the S.S. Columbia machines and the "Z" came the "A," which also had an iron base. Charles L. Clarke, January 8, 1929, with Edison at Menlo Park, NJ.