150 History of Luminescence 



his perpetual phosphor (mercury shaken in a glass phial) , a real 

 understanding of the source of the light was to come from electrical 

 experiments. William Gilbert's book, De Magnete (1600) , may be 

 considered the first dealing with the new science of electricity and 

 both von Guericke and Boyle made electrical experiments in the 

 seventeenth century, but Francis Hauksbee (died 1713), deserves 

 special acclaim as the inventor of a glass electrical machine used for 

 half a century, and as the first man to study electroluminescence 

 intensively in the laboratory. His interests also included capillarity, 

 density, and the cause of barometric changes, but his observations 

 on the light of rarified air in glass globes have had as great an 

 effect on modern illuminating art as the discovery of the Bolognian 

 phosphor one hundred years before. 



Hauksbee succeeded Hooke as Curator of Experiments of the 

 Royal Society. Little is known of his life except that his education 

 was slight and he had an inquiring mind, combined with a great 

 admiration for the learned. These characteristics appear in the title, 

 the dedication and the preface of his book, Physico-Mechanical 

 Experiments on Various Subjects, published in London in 1709, 

 with a second edition in 1719. The complete title is reproduced as 

 figure 23. 



In the preface, Hauksbee stated his credo as follows: " The 

 Learned World is now almost generally convinc'd, that instead of 

 amusing themselves with Vairi Hypotheses, which seem to differ little 

 from Romances, there's no other way of Improving natural phi- 

 losophy, but by Demonstrations and Conclusions founded upon 

 Experiments judiciously and accurately made." He then launched 

 into a description of his device for rotating and rubbing various 

 materials, particularly the glass vessels which could be evacuated 

 and in which he observed such striking luminous effects. The de- 

 tails of his experiments are presented in Chapter VII on electro- 

 luminescence. 



Hauksbee's Physico-Mechanical Experiments evidently exerted a 

 very considerable influence on the popular interest in natural phe- 

 nomena. In the 1720's a pamphlet appeared advertising " A Course 

 in Experimental Philosophy. To be perform'd by Benj. Worster ^ 

 A. M. and Tho. Watts, at the Academy or Accomplant's Office, for 

 qualifying young Gentlemen for Business, in Little Tower Street. 

 ..." The course was to be divided into (1) Mechanicks, (2) Hydro- 

 staticks, (3) Pneumaticks, and (4) Opticks. The demonstrators 

 had a good supply of apparatus. Among such matters as electrical 



^ Benjamin Worster (fl. 1720) , later wrote a book, A compendium and methodical 

 account of the principles of experimental philosophy (London, 1730) . 



