If your memory is good in most respects, but poor in a particular line, it is because you do not interest yourself in that line, and therefore have no material for association. Blind Tom's memory was a blank on most subjects, but he was a walking encyclopedia on music. [Sidenote: _Basic Principle of Thought-Reproduction_] _To improve your memory you must increase the number and variety of your mental associations._ Many ingenious methods, scientifically correct, have been devised to aid in the remembering of particular facts. These methods are based wholly on the principle that _that is most easily recalled which is associated in our minds with the most complex and elaborate groupings of related ideas_. [Sidenote: _Methods of Pick_] Thus, Pick, in "Memory and Its Doctors," among other devices, presents a well-known "figure-alphabet" as of aid in remembering numbers. Each figure of the Arabic notation is represented by one or more letters, and the number to be recalled is translated into such letters as can best be arranged into a catch word or phrase. To quote: "The most common figure-alphabet is this: 1 2 3 4 5 6 7 8 9 0 t n m r l sh g f b s d j k v p o ch c g qu z "To briefly show its use, suppose it is desired to fix 1,142 feet in a second as the velocity of sound, t, t, r, n, are the letters and order required. Fill up with vowels forming a phrase like 'tight run' and connect it by some such flight of the imagination as that if a man tried to keep up with the velocity of sound, he would have a 'tight run.'" [Sidenote: _Scientific Pedagogy_] The same principle is at the basis of all efficient pedagogy. The competent teacher endeavors by some association of ideas to link every new fact with those facts which the pupil already has acquired. In the pursuit of this method the teacher will "compare all that is far off and foreign to something that is near home, making the unknown plain by the example of the known, and connecting all the instruction with the personal experience of the pupil--if the teacher is to explain the distance of the sun from the earth, let him ask, 'If anyone there in the sun fired off a cannon straight at you, what should you do?' 'Get out of the way,' would be the answer. 'No need of that,' the teacher might reply; 'you may quietly go to sleep in your room and get up again; you may wait till your confirmation day, you may learn a trade, and grow as old as I am--_then only_ will the cannon-ball be getting near, _then_ you may jump to one side! See, so great as that is the sun's distance!'" We shall now show you how to apply this principle in improving your memory and in making a more complete use of your really vast store of knowledge. Rule I. _Make systematic use of your sense-organs._ [Sidenote: _How to Remember Names_]