,
i
√5, etc., are just as real as −3 · 5, √5, etc. It is impossible to look out of a window −3 · 5 times as it is to look out −3 · 5
i
times; strictly, one number is as ‘imaginary’ as the other, although the term has come by custom to apply to one and not to the other.
“4. The complex number 3 + 2
i
is now readily understood. Just as 3 + (−2) is graphically represented by starting from an arbitrary zero, passing 3 units in a positive direction (say to the right), then 2 units in the opposite direction, calling the sum the distance from 0 to the stopping-point, so 3 + 2
i