34 INTRODUCTION. 



ourselves, that we can scrutinize their appearance nearly as well 

 as if they had actually been brought a thousand times nearer to 

 us. For it was the increased precision of celestial observations 

 on the places and movements of the Planets, which furnished the 

 data whereon Kepler was enabled to base his statement of the 

 laws of their motion. It was the application of the pendulum to 

 the measurement of short inter\'als of time, that enabled Galileo 

 to ascertain the law of Falling Bodies. And it was not until the 

 precise measurement of a degree upon the surface of the Earth 

 had furnished the means of determining both its own diameter 

 and its distance from the Moon, that IS'ewton was enabled to 

 verify and establish his grand conception, of the identity of that 

 force which deflects the planets from a rectilineal course into 

 elliptical orbits, with that which draws a stone to the ground ; 

 and thus to establish that Law of Universal Gravitation, which 

 still remains the most comprehensive, as well as the most simple, 

 of all the generalizations, within which the intellect of man has 

 been able to comprehend the phenomena of Nature. So, again, 

 it was only when the elder ITerschel had developed new powers 

 in the telescope, that Sidereal Astronomy could be pursued with 

 any view much higher than that of mappiug the distribution of 

 the stars in the celestial sphere ; and the present state of our 

 knowledge of double, triple, and other combinations of stars, 

 with their mutually adjusted movements, of the multiform clus- 

 ters of luminous points which seem like repetitions of our own 

 firmament in remote deptlis of space, and of those nebulous films 

 which may be conceived to be new worlds and systems in pro- 

 cess of formation, has only been rendered attainable by the im- 

 provements which have been subsequently made in the construc- 

 tion of that majestic instrument. 



If we glance at the mode in which the fabric of our existing 

 Chemistry has been upreared, we at once see that it could not 

 have attained its present elevation and stability, but for the in- 

 strumentality of the perfected balance; by whose unerring indi- 

 cations it was that the first decisive blow was given to the old 

 "phlogistic" theory, that the foundation was laid for true ideas of 

 chemical combination, that the Laws of that Combination were 

 determined, and that the Combining Equivalents of different 

 elementary substances were ascertained ; and by whose means 

 alone can any of those analytical researches be prosecuted, which 

 are not only daily adding to our knowledge of the composition 

 of the bodies which surround us, and suggesting the most im- 

 portant applications of that knowledge to almost every depart- 

 ment of the Arts of Life, but which are preparing a broad and 

 secure foundation for a loftier and more comprehensive system 

 of Chemical Philosophy. 



So, again, the balance of torsion, the ingenious invention of 

 Cavendish and Coulomb, enables the Physical philosopher not 

 merely to render sensible, but to subject to precise measurement 



