The

**alphabet**then had 28**letters**, and so could be used to write the numbers 1 to 10, then 20 to 100, then 200 to 900, then 1000 (see Abjad numerals). In this numerical order, the new**letters**were put at the end of the**alphabet**.In November 1868 he changed the arrangement of the latter half of the

**alphabet**, O to Z, right-to-left. [3] : 12–20 In April 1870 he arrived at a four-row, upper case keyboard approaching the modern**QWERTY**standard, moving six vowel**letters**, A, E, I, O, U, and Y, to the upper row as follows: [3] : 24–25