sect. iv.] DISSERTATION SECOND. 123 



hypothesis does not relate to the explanation, but merely 

 to the expression of the fact ; it is 6rst assumed, and its 

 merit is then judged of synthetically, by its power to save, 

 to reconcile, or to represent appearances. At a time when 

 the mathematical sciences extended little beyond the ele- 

 ments, and when problems which could not be resolved by 

 circles and straight lines, could hardly be resolved at 

 all, such artifices as the preceding were of the greatest va- 

 lue. They were even more valuable than the truth itself 

 would have been in such circumstances ; and nothing 19 

 more certain than that the real elliptical orbits of the plan- 

 ets, and the uniform description of areas, would have been 

 very unseasonable discoveries at the period we are now 

 treating of. The hypotheses of epicycles, and of centres 

 of uniform motion, were well accommodated to the state of 

 science, and are instances of a false system which has 

 materially contributed to the establishment of truth. 



2. Copernicus and Tycho. 



On the revival of learning in Europe, astronomy was the 

 first of the sciences which was regenerated. Such, indeed, 

 is the beauty and usefulness of this branch of knowledge, 

 that, in the thickest darkness of the middle ages, the study 

 of it was never entirely abandoned. In those times of ig- 

 norance, it also derived additional credit from the assistance 

 which it seemed to give to an imaginary and illusive science. 

 Astrology, which has exercised so durable and extensive a 

 dominion over the human mind, is coeval with the first ob" 

 servations of astronomy. In the middle ages, remarkable 

 for the mixture of a few fragments of knowledge and truth 

 in a vast mass of ignorance and errour, it was assiduously 

 cultivated, and, in conjunction with alchemy and magick, 

 shared the favour of the people, and the patronage of the 



