DISSEETATION SIXTH. 



MATHEMATICAL AND PHYSICAL SCIENCE. 



CHAPTER I. 



INTRODUCTORY. 



1. On the Plan of this Dissertation. 



(i.) 



Modern 

 Advances 

 in Science. 



(2.) 

 Period 



THE year 1850 may be said to complete the Third cen- 

 tury of modern scientific progress, or the Fourth if 

 we include its earliest dawn. To each of these ages 

 of discovery may be assigned a peculiarity in the cha- 

 racter of its improvements, and even in the methods 

 which conduced to that improvement. 



Between 1450 and 1550 (a period so distinguished 

 in letters and the arts), some great truths in physics 

 )-1550. an( j mathematics had presented themselves to a few 

 precocious minds, yet they had not received any 

 public acknowledgment, nor perhaps an adequate de- 

 monstration. Algebra then first became a science. 

 Leonardo da Vinci made the earliest steps since the 

 time of Archimedes, in rational mechanics, and Co- 

 pernicus almost at the close of this period promul- 

 gated the true system of the world. 



But the next centenary (1550-1650) was the first 

 of true scientific activity. Its characteristic feature 

 was the vindication of observation and experiment as 

 the prime essentials to the increase of natural know- 

 ledge, with the consequent repudiation of the dogmas 

 of the schoolmen, and the baseless methods of ct priori 

 reasoning. The men of science formed a goodly array 

 at this stirring time ; and signal were their triumphs. 

 Galileo was beyond all comparison the glory of his 

 age. His sagacity, his knowledge, his versatility of 

 talent, his ingenuity as an inventor, his success in 

 prosecuting his discoveries, and his zeal and elo- 

 quence in making known their importance, gave him 

 an enviable pre-eminence even amidst a mighty gene- 

 ration. Bacon laid down the canons of a new method 



(3.) 

 Period 

 1550-1650. 



in philosophy which Gilbert and Kepler, as well as 

 Galileo, had already acted on. Napier and Descartes 

 prepared for the general application of mathematics 

 in the coming struggle. 



The hundred years which next succeeded (1650- 

 1750) saw the triumphant application of mathema- 

 tics to Mechanics and Physics, and the establishment 

 of the greatest mechanical theory of any age, that of 

 Gravitation. The preparatory labours of a hundred 

 and fifty years were brought, chiefly by the unparal- 

 leled sagacity and genius of Newton, to a speedy and 

 dazzling climax. His success brought numerous and 

 worthy labourers into the field, but they found enough 

 to do in gathering in the harvest which he had pre- 

 pared for them. 



If we look for the distinguishing characteristic of (5.) 



the centenary period iust elapsed (1750- 18 50), we p ( eriod , oe 

 n , .,.,,. r ,1 , -r ! V 11 1750-1850. 



nnd it in this, that it has drawn far more largely 



upon Experiment as a means of arriving at truth than 

 had previously been done. By a natural conversion 

 of the process, the knowledge thus acquired has 

 been applied with more freedom and boldness to 

 the exigencies of mankind, and to the farther in- 

 vestigation of the secrets of nature. If we com- 

 pare the now extensive subjects of Heat, Electri- 

 city, and Magnetism, with the mere rudiments of 

 these sciences as understood in 1750, or if we think 

 of the astonishing revival of physical and experi- 

 mental Optics (which had well nigh slumbered for 

 more than a century) during the too short lives of 

 Young and Fresnel, we shall be disposed to admit 



