Pan-American Exhibition in Buffalo in 1901 following its patent in August 1900 (patent no.656,085). It had all the familiar characteristics of the manual models, plus a QWERTY or a DHIATENSOR keyboard and all the advantages of later electric typewriters, including a light key touch, even typing, and automatic carriage return and line spacing. The machine was powered by an Emerson electric motor mounted on the rear and switched on by turning a Yale key on the side. The motor ran on 104 Volt 60 Hz AC electric current, which was not yet widely standard at the time. (See War of the currents) It is believed that the Blickensderfer Electric was produced from 1901 to 1919. Although a technological and engineering success, it was a commercial failure as at the time many homes and businesses were not wired for electricity. Electricity was primarily used for lighting and therefore not widely available during the daytime. The Blickensderfer Electrics were advertised and marketed in both France and Britain, although it is not known how many machines were ultimately sold. Very few machines are known to exist today, and they are found with both straight fronts and QWERTY keyboards or curved fronts and DHIATENSOR keyboards. Model 8 The Blickensderfer 8 introduced in 1908 was the first Blickensderfer to boast a tabulator system (see Tab stop), even though tabulators had been around for some time. This model was a considerable success and more were sold in 1908 than any other model. This machine was more massive and sturdier looking than the 7 with a two-piece typehead casting and a popular backspace mechanism. The tabulator used large nickel-plated levers placed on top of the machine, making it easy to operate. Production peaked in 1910 and declined until production ended in 1917. About 20,000 Blickensderfer 8's were produced, accounting for about 10% of all Blickensderfer models sold. Model 9 The Model 9, believed to be introduced in mid-1910, was similar in appearance to the Model 8, but lacked the nickel plated tabulator keys and also featured a folding ink roller arm support similar to the Blickensderfer Featherweight. Only about 10,000 machines were produced, ending in 1919. Innovation and technology On August 4, 1891, after several prototypes, Blickensderfer patented The Blickensderfer Type Writing Machine. The central component was the use of the cylindrical shaped interchangeable type element which he initially patented on July 15, 1890. An earlier variation