DISCOVERY 



95 



us to use a kind of imagery which is not our dominant 

 one. This is not a question which can be answered 

 with certainty at present, but all the indications of 

 experimental work seem to point in the direction of 

 an affirmative answer. For example, long-continued 

 learning of nonsense syllables by reading aloud or to 

 himself makes the subject of a memory experiment 

 approach to the auditory-motor type. Meumann states 

 that he began by being predominantly non-visual in his 

 learning of verbal matter, but that he cultivated visual 

 ideation to such an extent that he was able to learn 

 with it as well as with auditory or motor imagery, 

 and he found that his visual learning was slower but 

 more sure. That training can influence one's imagery 

 is assumed by those systems of memory training 

 which give exercises in visualisation, requiring their 

 pupils to practise the mental picturing of past scenes 

 and the discrimination of the details of those scenes. 

 We must wait, however, for more extensive experi- 

 mental investigation of the subject before we can be 

 sure of the effects of such training. 



A knowledge of the difference between the ideational 

 types also enables us to understand the difficulty 

 which some persons have in remembering certain 

 things, although they appear to have in other respects 

 what we call a good memory. Meumann tells the story 

 of a boy who was trying to draw a map of Greece. 

 Although he studied the map carefully by looking at 

 it, his reproduction was a mere shapeless blob. Meu- 

 mann surmised that he was of the motor type, and 

 made him trace the coast-line with his finger. The 

 boy was then able to reproduce the map without 

 difficulty. 



The last factor to be remembered in efficient memor- 

 isation is the part played by the previous organisation 

 of the mind in its reception of new material. New 

 knowledge is better remembered when the mind 

 receiving it is already stored with related ideas by 

 means of which the new matter may be at once under- 

 stood, assimilated, and brought into order. This is a 

 factor in remembering which can certainly be made 

 increasingly efficient. I suppose that the prime object 

 of the education of children is to increase their power 

 and ease of learning by such an increase in their mind 

 of the number of ideas which are already assimilated 

 and ready to be related to any new knowledge which 

 comes along. Let us imagine that a child of fifteen 

 who has received an ordinary school education, and 

 another child of the same age who has learned to read, 

 but is otherwise uneducated, are both presented with 

 a simple account of some facts equall}' new to both 

 of them. It will be found that the account will be 

 much better retained by the educated child. This 

 will still be true, if the account be of such a simple 

 nature that, in reading it, the uneducated child is 



able to understand it perfectly easily in every part. 

 The difference is due to the mass of related ideas in 

 the mind of the educated child into which the new 

 information can be fitted. 



The question with which we started this discussion 

 of memory was the question of whether psychological 

 research gave us any hope of improving our memories. 

 The answer seems to be very decidedly in the affirma- 

 tive, despite the pessimism of William Jones. We 

 have discussed four factors in remembering : the 

 attention, methods of learning, the imagery used in 

 remembering, and the organisation of the existing body 

 of knowledge in our minds. It is certain that most of 

 these factors are improvable, and it is probable that all 

 of them are. And, when we realise that the faculty 

 of memory as distinct from our methods of remember- 

 ing is merely a myth of out-of-date psychology, we 

 must conclude that the improvement of our methods 

 of remembering is the improvement of our memory. 



BOOKS RECOMMENDED 



The Economy and Training of Memory, by H. J. Watts, 

 (Edward Arnold & Co.) 



Experimental Psychology, by C. S. Myers, chap. v. (Cam- 

 bridge University Press, is. 6d.) 



More Adv.\nced 



Textbook of Experimental Psychology, by C. S. Myers, vol i, 

 chap. xii. (Cambridge University Press, gs.) 



Till' Psychology of Learning, by E. Meumann. English trans- 

 lation. New York, 1913. (D. Appleton & Co.) 



Movement and Mental Imagery, by Washburn. (Houghton 

 Mifflin Co., 1920, Si. 75.) 



The Life of a Radio- 

 Element 



By A. S. Russell, M.A., D.Sc. 



student of Christ Churdi, Oxford 



Radio-active elements differ notably from ordinar\^ 

 matter in that they lack permanence. The ordinary 

 elements seem made for all time ; not so the radio- 

 elements. They change. Each has a life ; of some 

 it might almost be said they have a career. 



A radio-element is usually defined as one which 

 emits spontaneously a a- or /3-particles. Atoms 

 which emit these particles are said to disintegrate. 

 The a is a particle of matter which is equal in weight 

 to four hydrogen atoms, carries two charges of posi- 

 tive electricity, and is expelled from the centre of the 

 atom with a velocity of about 20,000 miles per second. 

 The /3 is a single charge of negative electricity (and 



