After a time the mind will become accustomed to the drill, and will even begin to enjoy it. Give it some variety by occasionally changing the objects of examination. The object need not always be something to be looked at. Instead, select some subject in history or literature, and "run it down," endeavoring to bring to light all the facts relating to it that are possible to you. _Anything_ may be used as the subject or object of your inquiry; but what is chosen must be held in the field of conscious attention firmly and fixedly. The habit once acquired, you will find the practice most fascinating. You will invent new subjects or objects of inquiry, investigation, and thought, which in themselves will well repay you for your work and time. But never lose sight of the main point--the development of the power of voluntary attention.
In studying the methods of developing and training the voluntary attention, the student should remember that _any_ exercise which develops the will, will result in developing the attention; and, likewise, any exercise which develops the voluntary attention will tend to strengthen the will. The will and attention are so closely bound together that what affects one also influences the other. This fact should be borne in mind, and the exercises and practices based upon it.
In practicing concentration of voluntary attention, it should be remembered that concentrating consists not only of _focusing_ the attention upon a given object or subject, but also of the _shutting out_ of impressions from other objects or subjects. Some authorities advise that the student endeavor to listen to one voice among many, or one instrument among the many of a band or orchestra. Others advise the practice of concentrating on the reading of a book in a room filled by persons engaged in conversation, and similar exercises. Whatever aids in _narrowing the circle_ of attention at a given moment tends to develop the power of voluntary attention.
The study of mathematics and logic is also held to be an excellent practice in concentration of voluntary attention, inasmuch as these studies require close concentration and attention. Attention is also developed by any study or practice which demands _analysis_ of a whole into its parts, and then the _synthesis_ or building up of a whole from its scattered parts. Each of the senses should play a part in the exercises, and in addition to this the mind should be trained to concentrate upon some one idea held within itself--some mental image or abstract idea existing independently of any object of immediate sense report.