Why the string variable values been changed when I use the '+' connection.

Why the string variable values been changed when I use the '+' connection.

code:
var
  S: RawByteString;
begin
  S :=#$E0#$02#$00#$04#$00#$00#$00#$00#$E0#$01#$00 +
    #$9F#$41;
  Memo1.Lines.Add(S);
end;