EXAMPLES OF THE EXPLANATION OF LAWS. 285 



were generalizations fi-om experience before they were deduced from 

 first principles. The (][uadratnro of the cycloid was first effected by 

 measurement; or rather by weighing a cycloidal card, and comparing 

 its weight with that of a piece oi" shnilar card of known dimensions. 



§ 6. To the foregoing examples from physical science, let' us add an- 

 other from mental. The following is one of the simple laws of mind : 

 Ideas of a pleasurable or pahiful character form associations more easily 

 and strongly than other ideas, that is, they bi'come associated after fewer 

 I'epetitions, and the association is more durable. This is an experi- 

 mental law, grounded upon the Method of Difference. By deduction 

 from this law, many of the more special laws which experience showa 

 to exist among particular mental phenomena may be demonstrated 

 and explained : — the ease and rapidity, for instanccy^with which thoughts 

 connected with our passions or our more cherished interests are exci- 

 ted, and the finn hold which the facts relating to them have on our 

 memoiy ; the rixid recollection we retain of minute circumstances 

 which accompanied any object or event that deeply interested us, and 

 of the times and places in which we have been very happy or very 

 miserable ; the horror with Avhich we view ' the accidental instru- 

 ment of any occurrence which shocked us, or the locality where it 

 took place, and the pleasure we derive fi-om any menwrial of past 

 enjoyment ; all these effects being proportional to the sensibility of 

 the indi\-idual mind, and to the consequent intensity of the pain or 

 pleasure from which the association originated. It has been suggested 

 by the able %vriter of a biogiaphical sketch of Dr. Priestley, in one of 

 our monthly periodicals, that the same elementary law of our mental 

 constitution, suitably followed out, would explain a variety of mental 

 phenomena hitherto inexplicable, and in particular some of the funda- 

 mental diversities of human character and genius. Our associations 

 being of two sorts, either between synchronous, or between successive 

 impressions ; and the influence of the law which, renders associations- 

 stronger in proportion to the pleasurable or painful character of the 

 impressions, being felt with peculiar force in the synchronous class of 

 associations ; it is remarked by the writer refeired to, that in minds of 

 strong organic sensibility synchronous associations will be likely to 

 predominate, producing a tendency to conceive things in pictures and 

 m the concrete, clothed in all their attributes and chcumstances, a 

 mental' habit which is commonly called Imagination, and is one of the 

 peculiarities of the painter and the poet ; while persons of more modern 

 ate susceptibility to plciisure and pain will have a tendency to asso- 

 ciate facts chiefly in the order of tlieir succession, and if they possess 

 mental superiority, will addict themselves to history or science rather 

 than to creative art. This interesting speculation the author (jf the 

 present work has endeavored, on another occasion, to pursue further, 

 and to explain, by means of it, the leading peculiarities of the poetical 

 temperament. It is at least an example which may sei-ve, instead of 

 many others, to show the extensive scope which exists for deductive 



an equable pressure, produced by a bladder partially filled with air. The pressure, by 

 keeping back the blood from the part prevents the inllainination, or the tumor, from being 

 nourished : in the case of inflamiiialion, it removes the stimulus, which the organ is unfit 

 to receive: in the case of tumors, by keeping back the nutritive fluid, it causes the absorp- 

 tion of matter to exceed the supply, and the diseased misa is gradually absorbed and dis- 

 appears. ' , ' , 



