An effort has been made in the preparation of this book, to provide for the student those things which are of fundamental importance in his initial study of the subject, together with a careful presentation of some of the more important points that are usually left for him to acquire during his office experience after he has left school. In preparing this book, efforts were made to provide the student with those things that are fundamental to his initial study of the subject, together with a careful presentation of some of the most important points that are usually left to him. purchase while working in the office after graduation.