OBSERVATION AND DESCRIPTION. 189 



of the earth is globular is inferred from certain marks, as for 

 instance from this, that its shadow thrown upon the moon is 

 circular ; or this, that on the sea, or any extensive plain, our 

 horizon is always a circle ; either of which marks is incom- 

 patible with any other than a globular form. I assert further, 

 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 propositions, 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 organs and that 

 position are wanting. This identification of the earth, first as 

 a globe, and next as an oblate spheroid, 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 inferred. But we could not 

 without impropriety call either of these assertions an induc- 

 tion from facts respecting the earth. They are not general 

 propositions collected from particular facts, but particular 

 facts deduced from general propositions. They are conclu- 

 sions obtained deductively, from premises originating in 

 induction: but of these premises some were not obtained 

 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 ellipticity, 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 



