Why does Mr. Jabez Wilson write so much in "The Red-Headed League"?

Mr. Jabez-Wilson writes so much in "The Red-Headed League" because he takes up a useless job for The Red-Headed League, which is an office for males with ginger hair. He is told to copy the Encyclopedia Britannica, which has loads of pages and is one of the biggest books in history. When he goes up to Sherlock Holmes to let him know of this weird sort of engagement, he has not even finished copying all of the information under the letter "A".