2 THE POPULAR SCIENCE MONTHLY. 



which the external senses could never discover, such as the transub- 

 stantiation of bread. 



Four centuries later, the more celebrated Bacon, in the first book 

 of his " Novum Organum," gave his clear account of exjDerience as 

 something which must be open to verification and reexamination. 

 But, superior as Lord Bacon's conception is to earlier notions, a mod- 

 ern reader who is not in awe of his grandiloquence is chiefly struck 

 by the inadequacy of his view of scientific procedure. That we have 

 only to make some crude experiments, to draw up briefs of the re- 

 sults in certain blank forms, to go through these by rule, checking 

 off everything disproved and setting down the alternatives, and that 

 thus in a few years physical science would be finished up what an 

 idea ! " He wrote on science like a Lord Chancellor," indeed. 



The early scientists, Copernicus, Tycho Brahe, Kepler, Galileo, 

 and Gilbert, had methods more like those of their modern brethren. 

 Kepler undertook to draw a curve through the places of Mars ; ' and 

 his greatest service to science was in impressing on men's minds that 

 this was the thing to be done if they wished to improve astronomy ; 

 that they were not to content themselves with inquiring whether 

 one system of epicycles was better than another, but that they were 

 to sit down to the figures and find out what the curve, in truth, was. 

 He accomplished this by his incomparable energy and courage, blun- 

 dering along in the most inconceivable way (to us), from one irra- 

 tional hypothesis to another, until, after trying twenty-two of these, 

 he fell, by the mere exhaustion of his invention, upon the orbit which 

 a mind well furnished with the weapons of modern logic would have 

 tried almost at the outset. 



In the same way, every work of science great enough to be re- 

 membered for a few generations affords some exemplification of the 

 defective state of the art of reasoning of the time when it was writ- 

 ten ; and each chief step in science has been a lesson in logic. It was 

 so when Lavoisier and his contemporaries took up the study of chem- 

 istry. The old chemist's maxim had been, " Lege, lege, lege, labora, 

 ora, et relege" Lavoisier's method was not to read and pray, not to 

 dream that some long and complicated chemical process would have 

 a certain effect, to put it into practice with dull patience, after its in- 

 evitable failure to dream that with some modification it would have 

 another result, and to end by publishing the last dream as a fact : 

 his way was to carry his mind into his laboratory, and to make of his 

 alembics and cucurbits instruments of thought, giving a new concep- 

 tion of reasoning, as something which was to be done with one's eyes 

 open, by manipulating real things instead of words and fancies. 



The Darwinian controversy is, in large part, a question of logic. 

 Mr. Darwin proposed to apply the statistical method to biology. The 

 same thing had been done in a widely different branch of science, the 

 1 Not quite so, but as nearly so as can be told in a few words. 



