OBSERVATION AND DESCRIPTION. 



423 



any extensive plain, our horizon is 

 always a circle ; either of which 

 marks is incompatible with any other 

 than a globular form. I assert fur- 

 ther, that the earth is that particular 

 kind of globe which is termed an 

 oblate spheroid, because it is found 

 by measurement in the direction of 

 the meridian that the length on the 

 surface of the earth which subtends a 

 given angle at its centre diminishes 

 as we recede from the equator and 

 approach the poles. But these pro- 

 positions, that the earth is globular, 

 and that it is an oblate spheroid, 

 assert, each of them, an individual 

 fact, in its own nature capable of 

 being perceived by the senses when 

 the requisite organs and the necessary 

 position are supposed, and only not 

 actually perceived because those or- 

 gans and that position are wanting. 

 This identification of the earth, first 

 as a globe, and next as an oblate 

 ppheroid, which, if the fact could have 

 been seen, would have been called a 

 description of the figure of the earth, 

 may without impropriety be so called 

 when, instead of being seen, it is in- 

 ferred. But we could not without 

 impropriety call either of these asser- 

 tions an induction from facts respect- 

 ing the earth. They are not general 

 propositions collected from particular 

 facts, but particular facts deduced 

 from general propositions. They are 

 conclusions obtained deductively from 

 premises originating in induction ; but 

 of these premises some were not ob- 

 tained by observation of the earth, 

 nor had any peculiar reference to it. 



If, then, the truth respecting the 

 figure of the earth is not an induction, 

 why should the truth respecting the 

 figure of the earth's orbit be so ? The 

 two cases only differ in this, that the 

 form of the orbit was not, like the 

 form of the earth itself, deduced by 

 ratiocination from facts which were 

 marks of ellipticitv, but was got at by 

 boldly guessing that the path was an 

 ellipse, and finding afterwards, on 

 examination, that the observations 

 were in harmony with the hypothesis. 



According to Dr. Whewell, however, 

 this process of guessing and verifying 

 our guesses is not only induction, but 

 the whole of induction ; no other ex- 

 position can be given of that logical 

 operation. That he is wrong in the 

 latter assertion, the whole of the pre- 

 ceding Book has, I hope, suflBciently 

 proved ; and that the process by 

 which the ellipticity of the planetary 

 orbits was ascertained is not induc- 

 tion at all was attempted to be shown 

 in the second chapter of the same 

 Book.* We are now, however, pre- 

 pared to go more into the heart of 

 the matter than at that earlier period 

 of our inquiry, and to show, not 

 merely what the operation in question 

 is not, but what it is. 



§ 4. We observed, in the second 

 chapter, that the proposition "the 

 earth moves in an ellipse," so far as it 

 only serves for the colligation or con- 

 necting together of actual observa- 

 tions, (that is, as it only affirms that 

 the observed positions of the earth 

 may be correctly represented by as 

 many points in the circumference of 

 an imaginary ellipse,) is not an induc- 

 tion, but a description ; it is an in- 

 duction only when it affirms that the 

 intermediate positions, of which there 

 has been no direct observation, would 

 be found to correspond to the re- 

 maining points of the same elliptic 

 circumference. Now, though this 

 real induction is one thing and the 

 description another, we are in a very 

 different condition for making the in- 

 duction before we have obtained the 

 description, and after it. For inas- 

 much as the description, like all other 

 descriptions, contains the assertion of 

 a resemblance between the phenome- 

 non described and something else ; 

 in pointing out something which the 

 series of observed places of a planet 

 resembles, it points out something in 

 which the several places themselves 

 agree. If the series of places corre- 

 spond to as many points of an ellipse, 



* Supra, book iii. cb. ii. J 3, 4, 5. 



