It has been pointed out that in an act of memory there must be a recognition of the present experience as one which has occurred in a series of past events. The definite reference of a memory image to a past series is sometimes spoken of as localization. The degree to which a memory image is localized in the past differs greatly, however, in different cases. Your recollection of some interesting personal event in your past school history may be very definitely located as to time, image after image reinstating themselves in memory in the order of their actual occurrence. Such a similar series of events must have taken place when, by means of handling a number of objects, you learned different number and quantity relations or, by drawing certain figures, discovered certain geometrical relations. At the present time, however, although you remember clearly the general relations, you are utterly unable to recall the more incidental facts connected with their original presentation, or even localize the remembered knowledge at all definitely in past time. Nothing, in fact, remains as a permanent possession except the general, or scientific, truth involved in the experience. CLASSIFICATION OF MEMORIES =A. Mechanical.=--The above facts would indicate that in many cases the mind would find it more effective to omit from conscious recall what may appear irrelevant in the original presentation, and fix attention upon only the essential features. From this standpoint, two somewhat different types of memory are to be found among individuals. With many people, it seems as if a past experience must be revived in every detail. If such a one sets out to report a simple experience, such as seeing a policeman arrest a man on the street, he must bring in every collateral circumstance, no matter how foreign to the incident. He must mention, for example, that he himself had on a new straw hat, that his companion was smoking a cigar, was accompanied by his dog, and was talking about his crops, at the time they observed the arrest. This type is known as a mechanical memory. Very good examples of such will be seen in the persons of "Farmer Philip" in Tennyson's _Brook_ and the "landlady" in Shakespeare's _King Henry IV_. =B. Logical.=--In another type of memory, the mind does not thus associate into the memory experience every little detail of the original experience. The outstanding facts, especially those which are bound by some logical sequence, are the only ones which enter into permanent association. Such a type of mind, therefore, in recalling the past, selects out of the mass of experiences the incidents which will constitute a logical revival, and leaves out the trivial and incidental. This type is usually spoken of as a logical memory. This type of memory would, in the above incident, recall only the essential facts connected with the arrest, as the cause, the incidents, and the result. MEMORY IN EDUCATION