THE practical importance of the fact of mental imagery and of the individual differences in power of mental imagery is very great. They should be particularly taken into account in any business or profession in which one seeks to implant knowledge or conviction in the mind of another.

The underlying principle in such cases is this: To the mind you are seeking to convince or educate, present your facts in as many different ways and as realistically as possible, so that there may be a variety of images, each serving as a clue to prompt the memory.

We cannot do more at this point than indicate a few minor phases of the practical application of the principles of mental imagery.

In the old days geography was taught simply with a book and maps. Today children also use their hands in molding relief maps in sand or clay, and mountains and rivers have acquired a meaning they never had before.

In the days of the oral "spelling match" boys and girls were better spellers than products of a later school system, because they used not only the eye to see the printed word, the arm and hand to feel in writing it, but also the ear to hear it and the vocal muscles to utter it. And because of this fact oral spelling is being brought back to the schoolroom.

If you have pianos to advertise, do not limit your advertisement to a beautiful picture of the mahogany case and general words telling the reader that it is "the best." Pianos are musical instruments, and the descriptive words should first of all call up delightful auditory images in your reader's mind.

If you have for sale an article of food, do not simply tell your customer how good it is. Let him see it, feel it, and particularly taste it, if you want him to call for it the next time he enters your store.

Turn, for example, to the advertisement of a certain brand of chocolate, facing page 6. The daintily spread table, the pretty girl, the steaming cup, the evident satisfaction of the man, who looks accustomed to good living, - these elements combine in a skilful appeal to the senses. Turn now to another advertisement of this same brand of chocolate, shown facing page 22. The purpose here is to inform you as to the large quantity of cocoa beans roasted in the company's furnaces. Whether this fact is of any consequence or not, the impression you get from the picture is of a wheelbarrow full of something that looks like coal being trundled by a dirty workman, while the shovel by the furnace door and the cocoa beans scattered about the floor remind one of a begrimed iron foundry.

The only words that will ever sell anything are graphic words, picturesque words, words that call up distinct and definite mental pictures of an attractive kind.

The more sensory images we have of any object the better we know it.

If you want to make a first impression lasting, make it vivid. It will then photograph itself upon the memory and arouse the curiosity.

A boy who is a poor visualizer will never make a good artist. A man who is a poor visualizer is out of place as a photographer or a picture salesman.

No person with weak auditory images should follow music as a profession or attempt to sell phonographs or musical instruments or become a telephone or telegraph operator or stenographer.

No man who can but faintly imagine the taste of things should try to write advertisements for articles of food.

Remember the rule: To the mind you are seeking to convince or educate present your facts in as many different ways and as realistically as possible, so that there may be a variety of images, each serving as a clue to prompt the memory.

You can put this rule to practical use at once. Try it. You will be delighted with the result.