"Generally speaking, all typewriters resolve themselves into two styles of keyboard machine: in one the type bars strike the paper when the keys are depressed; in the other the type is arranged around a wheel which rotates in answer to the depressing of a keyboard letter, and prints the corresponding type which is thereby brought opposite the printing point. Either variety is good. It is a matter of preference. Possibly the type-bar kind is the more common. There is, too, a difference in the manner of inking the type. One machine inks the letters from an inked ribbon that is drawn along by the action of the machine between the type face and the paper; the type of the other machine is inked from an ink pad that strikes the type before it is brought in contact with the paper. Sometimes this ribbon or ink pad is black; sometimes blue, green, red, or purple. Sometimes, too, a ribbon is so constructed that it inks in two colors, which is frequently a convenience for business purposes. Text, for example, can be done in black and the numerals--prices perhaps--put in in red." "I see. I should think that would be fine," said Paul. "Now tell me one other thing: are the letters arranged in the same order on all typewriters?" "You mean the keyboards?" "Yes, I guess that is what I mean," replied Paul. "Keyboards sometimes differ in arrangement," Mr. Cameron explained. "Some keyboards have a key for each letter, and others one key for several characters. It is, however, desirable that machines should differ as little in arrangement as possible, as typists learn a universal method of letter-placing and are consequently annoyed to find the letters in an unfamiliar location on a new machine." "I can see that would upset them dreadfully," answered Paul. "Of course they could not go so fast." "Not only that, but they would make frequent mistakes," continued his father. "The most expert typists seldom look at the keys, you know. They memorize the position of the letters and then operate the machine by the touch system, or by feeling. You have often seen a person play the piano in the same fashion. It is a great advantage for a stenographer to be able to do this, for he can keep his eyes on his copy and not constantly change his eye-focus by glancing first at the manuscript and then at the machine. He can also give his entire attention to taking dictation if he so desires. The touch system is a great timesaver; it enables any one to make twice the speed." "And the bell warns them that they are approaching the end of a line, even if they don't see that they are," Paul added. "Precisely!" "It is a great scheme, isn't it--a typewriter?" declared the boy. Mr. Cameron nodded. "What wouldn't the old monks have given for one?" went on Paul mischievously. "Think of the years of work that would have saved them."