On page 192, I mention that an excellent photograph of the Bennett Elevator (built in 1863) was published in Frank Severance's A Picture Book of Earlier Buffalo (published in 1913) and reprinted in Reyner Banham's A Concrete Atlantis: U.S. Industrial Building and European Modern Architecture 1900-1925 (published in 1986). Adjacent to the Evans Slip and facing Buffalo Creek, the Bennett was designed and built by Robert Dunbar on the very spot upon which the pioneering Dart Elevator stood from 1843 until it burned down on 8 September 1862 (cf. "Fire in Buffalo," New York Times, September 9, 1862).
Note well that in this story the Times refers to the old Dart Elevator as "D.S. Bennett's Elevator," not Joseph Dart's Elevator. According to J.N. Larned, author of A History of Buffalo, Delineating the Evolution of the City, Volume I (published 1911),
the Dart elevator, purchased after some years by Mr David S. Bennett, was burned in 1863 and rebuilt by Mr Bennett on a greatly enlarged scale, having a storage capacity of 600,000 bushels. For many years this Bennett elevator was representative of the highest development of elevator construction.
But no one seems to know exactly when Joseph Dart sold his elevator to David Bennett. Likely times would have been around 1846, when "his" elevator was doubled in size and speed, and during or after the Panic of 1857.
As for the Bennett Elevator being "representative of the highest development of elevator construction," J.N. Larned was obviously referring to the period between 1860 and 1900, that is, before steel was used in the construction of both grain bins and the structures that contained them. Incredibly capacious though they may have been, the grain bins inside the Bennett Elevator were still made of wood and, though clad in iron, the main house was also (still) made of wood. And yet the Bennett was so well-designed that it remained standing until 1912, when it was finally taken down.
Note well that the engine/boiler room was located within the main house and very close to the marine tower. (Note the proximity of the smokestack to the "super tower" that clearly contains the top part of the elevating leg.) Typical of elevator-design in the 19th century, this arrangement was used because it minimized the distance that the elevator's various ropes and belts would need to travel to get power from the engine/boiler room to the elevator's primary machines. But it also increased the risk that sparks created by the mechanical apparatus would ignite the clouds of grain dust that inevitably collected in the marine tower and the main house itself.
And so, the surpassing of the "highest development of elevator construction" represented by the Bennett Elevator was not only driven by the switch from wood to steel, which was made to minimize the likelihood of and/or damages caused by grain-dust explosions. It was also driven by the idea that, in order to further minimize explosions, the elevator's functions should be distributed among three, spatially distinct buildings (the powerhouse, the marine tower, and the mainhouse). Should an explosion occur in one building, it would not spread to the others.