210 PHYSICAL SCIENCE IN THE MIDDLE AGES. 



the mariner's compass, the reformed calendar, the decimal notation, 

 algebra, trigonometry, chemistry, counterpoint, an invention equivalent 

 to a new creation of music ; these are all possessions which we inherit 

 from that which has been so disparagingly termed the Stationary Pe- 

 riod. Above all, let us look at the monuments of architecture of this 

 period ; the admiration and the despair of modern architects, not only 

 for their beauty, but for the skill disclosed in their construction. With 

 all these evidences before us, how can we avoid allowing that the mas- 

 ters of the middle ages not only made some small progress in Astron- 

 omy, which has, grudgingly as it would seem, been admitted in a former 

 Book ; but also that they were no small proficients in other sciences, 

 in Optics, in Harmonics, in Physics, and, above all, in Mechanics? 



If, it may be added, we are allowed, in the present day, to refer to 

 the perfection of our arts as evidence of the advanced state of our 

 physical philosophy ; if our steam-engines, our gas-illumination, our 

 buildings, our navigation, our manufactures, are cited as triumphs of 

 science ; shall not prior inventions, made under far heavier disadvan- 

 tages, shall not greater works, produced in an earlier state of kuowl- 

 eclo-e, also be admitted as witnesses that the middle ages had their 



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share, and that not a small or doubtful one, of science ? 



To these questions I answer, by distinguishing between Art, and 

 Science in that sense of general Inductive Systematic Truth, which it 

 bears in this work. To separate and compare, with precision, these 

 two processes, belongs to the Philosophy of Induction ; and the attempt 

 must be reserved for another place : but the leading differences are 

 sufficiently obvious. Art is practical, Science is speculative : the for- 

 mer is seen in doing ; the latter rests in the contemplation of what is 

 known. The art of the builder appears in his edifice, though he may 

 never have meditated on the abstract propositions on which its stability 

 and strength depends. The Science of the mathematical mechanician 

 consists in his seeing that, under certain conditions, bodies must sustain 

 each other's pressure, though he may never have applied his knowledge 

 in a single case. 



Now the remark which I have to make is this : in all cases the 

 Arts are prior to the related Sciences. Art is the parent, not the 

 progeny, of Science ; the realization of principles in practice forms 

 part of the prelude, as well as of the sequel, of theoretical discovery. 

 And thus the inventions of the middle ages, which have been above 

 snumerated, though at the present day they may be portions of our 

 sciences, are no evidence that the sciences then existed ; but only that 



