CHAPTER V 



THE EIGHTEENTH CENTURY 



hitroduction 



AS JOHN DRYDEN extollcd the remarkable advances of science in the 

 l\ seventeenth century, so Joseph Priestley heralded the state of 

 knowledge during the eighteenth. Speaking of conditions since the 

 revival of letters in Europe, Priestley (1772: 30) wrote that there 

 were " those who consider the world as having now arrived at the 

 state of perfect manhood with respect to science," and that whoever 

 " shall reflect upon the astonishing improvements that have been 

 made ... in all branches of real knowledge, in little more than two 

 centuries that have elapsed [since] the expiration of that long period 

 of darkness, cannot help forming the most glorious expectations." 



The eighteenth century has been called the " Age of Reason " 

 or the " Age of Enlightenment," Knowledge did increase at a 

 rapid pace. Many science academies, both national and local, were 

 started— the Russian Academy at St. Petersburg (1725) , the Swedish 

 Academy at Stockholm (1739) , the Royal Academy of Denmark at 

 Copenhagen (1742) , the American Philosophical Society at Phila- 

 delphia (1743) . Local Institutes appeared in various cities, Bor- 

 deaux in 1703, Montpellier in 1706, etc. Journals, textbooks, and 

 encyclopedias made knowledge available to all. 



The first book of the eighteenth century to treat a luminescence 

 in some detail was Francis Hauksbee's Physico-mechanical Experi- 

 meyits (1709) . Among other things, it described the light produced 

 by rubbing evacuated " bottles." It will serve as a proper historical 

 beginning to focus attention on a new type of luminescence, now all 

 important to modern living. Moreover, this new light was associated 

 with electricity, and the eighteenth century deserves, above all, to be 

 remembered as the century when interest in electricity was para- 

 mount. The names of Franklin, Beccaria, Nollet, Gray, Dufay, 

 Desaguliers, van Musschenbroek, and many others come to mind, 

 but the first important experiments were those of Hauksbee. 



Francis Hauksbee and Electroluminescence 



Although Jean Picard had noted the light of a mercury barometer 

 when shaken in the dark in 1675, and much discussion of the phe- 

 nomenon appeared around 1700 after Johann Bernoulli described 



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