The way to train the mind to receive clear sight-impressions, and therefore to retain them in the memory is simply to concentrate the will and attention upon objects of sight, endeavoring to _see_ them plainly and distinctly, and then to practice recalling the details of the object some time afterward. It is astonishing how rapidly one may improve in this respect by a little practice. And it is amazing how great a degree of proficiency in this practice one may attain in a short time. You have doubtless heard the old story of Houdin, the French conjurer, who cultivated his memory of sight impressions by following a simple plan. He started in to practice by observing the number of small objects in the Paris shop windows he could see and remember in one quick glance as he rapidly walked past the window. He followed the plan of noting down on paper the things that he saw and remembered. At first he could remember but two or three articles in the window. Then he began to see and remember more, and so on, each day adding to his power of perception and memory, until finally he was able to see and remember nearly every small article in a large shop window, after bestowing but one glance upon it. Others have found this plan an excellent one, and have developed their power of perception greatly, and at the same time cultivated an amazingly retentive memory of objects thus seen. It is all a matter of use and practice. The experiment of Houdin may be varied infinitely, with excellent results. The Hindus train their children along these lines, by playing the "sight game" with them. This game is played by exposing to the sight of the children a number of small objects, at which they gaze intently, and which are then withdrawn from their sight. The children then endeavor to excel each other in writing down the names of the objects which they have seen. The number of objects is small to begin with, but is increased each day, until an astonishing number are perceived and remembered.