458 



THE INTELLECTUAL RISE IN ELECTRICITY. 



His starting-point is the strange light seen in the mer- 

 curial barometer, the cause of which it is his task to dis- 

 cover. Like Bernouilli, he calls it the "mercurial phos- 

 phorus." In common with others, he believes the radi- 

 ance to be due to some quality of the mercury, brought 

 into action by the peculiar conditions of vacuum, or agita- 

 tion, or both. The Cartesian theory had few adherents 

 among the English philosophers of the time, and certainly 

 Hauksbee was not among them. 



From the moment he begins his experiments (1705) the 

 results astonish him. It must be borne in mind that, at 

 the outset, he had no suspicion that the mercury light had 

 anything to do with electricity. As I have already stated, 

 these odd luminosities, which did not appear to be the 

 immediate consequence of actual burning, were all grouped 

 together, and the effort was often made to refer them to 

 some common origin. Even Newton 1 held this belief. 

 "Do not all bodies," he asks, "which abound with terres- 

 trial parts, and especially with sulphurous ones, emit light 

 as often as those parts are sufficiently agitated; whether 

 that agitation be made by heat, or by friction, or percus- 

 sion, or putrefaction, or by any vital motion on any other 

 cause? As, for instance, sea-water in a raging storm; 

 quicksilver agitated in vacuo; the back of a cat or neck 

 of a horse, obliquely struck or rubbed, in a dark place; 

 wood, flesh and fish, while they putrefy; vapors arising 

 from putrefied waters, usually called Ignes Fatui; stacking 

 of moist hay or corn growing hot by fermentation; glow- 

 worms and the eyes of some animals by vital motions; the 

 vulgar phosphorus, agitated by the attrition of any body or 

 by the particles of the air; amber and some diamonds, by 

 striking, or pressing, or rubbing them; scrapings of steel, 

 struck off with a flint; iron hammered very nimbly till it 

 become so hot as to kindle sulphur thrown upon it." Ob- 

 viously there was no more reason why Hauksbee, in the 

 beginning, should have supposed the barometer light to be 



1 Optics. Q. 8. 



