ADDRESS. Ixxix 



portance to those who are working in the same direction. They verify in 

 various ways the statements of the first discoverer, and seldom fail to uoticc 

 further particulars, and to correct any little errors of detail into which he 

 may have fallen. They soon make it a stepping-stone to further disco- 

 veries. Any thing like wilful misrepresentation is inevitably detected and 

 made known. 



It must not, however, he supposed that the investigator drifts imcon- 

 sciously into the habit of truthfulness for want of temptation to be un- 

 truthful, or even that error presents itself to his mind in a grotesque and 

 repulsive garb, so as to enlist from the iirst his feelings against it j for I 

 can assure you that the precise contrary of these things happens. Error 

 comes before him usually in the very garb of truth ; and his utmost skill 

 and attention are needed to decide whether or not it is entitled to retain that 

 garb. 



You will easily see how this happens if you reflect that each working 

 hypothesis employed by an investigator is an uuproven proposition, which 

 bears such resemblance to truth as to give rise to hopes that it may really be 

 true. The investigator trusts it provisionally to tlie extent of trying one or 

 more experiments, of which it claims to predict the specific result. Even 

 though it guide him correctly for a while, he considers it still on trial until 

 it has been tested by every process which ingenuity can suggest for the pur- 

 pose of detecting a fault. 



Most errors which an experimentalist has to do with are really imperfect 

 truths, which have done good service in their time by guiding the course of 

 discovery. The great object of scientific work is to replace these imper- 

 fect truths by more exact and comprehensive statements of the order of 

 nature. 



Whoever has once got knowledge from nature herself by truthful reason- 

 ing and experiment, must be dull indeed if he does not feel that he has ac- 

 quired a new and noble power, and if he does not long to exercise it further, 

 and make new conquests from the realm of darkness by the aid of known 

 truths. 



The habit of systematically searching for truth by the aid of known truths, 

 and of testing the validity of each step by constant reference to nature, has 

 now been practised for a sufficiently long time to enable us to judge of some 

 of its results. 



Every true idea of the order of nature is an instrument of thought. It 

 can only be obtained by truthful investigation ; and it can only be used effec- 

 tively in obedience to the same laws. But the first idea which is formed of 

 any thing occurring in nature affords only a partial representation of the 

 actual reality, by recording what is seen of it from a particular point of view. 

 By examining a thing from different points of view we get different ideas of 

 it ; and when we compare these ideas accurately with one another, recollect- 

 ing how each one was obtained, we find that they really supplement each 

 other. 



We try to form in our minds a distinct image of a thing capable of pro- 

 ducing these various appearances ; and when we have succeeded in doing so, 

 we look at it from the different points of view from which the natural object 

 had been examined, and find that the ideas so obtained meet at the central 

 image. It usually happens that an accurate examination of the mutual 

 bearings of these ideas on the central image suggests additions to them, and 

 correction of some particulars in them. 



Thus it is that true ideas of a natural phenomenon confirm and strengthen 



r/2 ■ 



