430 History of Luminescence 



finally decided that " contact of fresh external Air might contribute 

 to this peculiar kind of agitation in the Gummous Noctiluca, as an 

 helpful thing, and in the Aerial Noctiluca, as an almost necessary 

 concurrent." 



He also noticed that some of his noctiluca rubbed in the hands 

 gave not uniform flames but " often seemed to tremble much, and 

 sometimes, as it were, to blaze out with sudden flashes, that were not 

 lasting (which put me in mind of some of the faculae solares) ." A 

 great store of whitish smoke arose and " other Effluviums . . . imbued 

 the neighboring Air with a ranck and offensive smell." ^ There was 

 practically no heat but the appearance was like an artificial ignis 

 lambens, reminding Boyle of Virgil's lines in the Aeneid, describ- 

 ing the flame on the head of Julus. 



In order to test the effect of a vacuum, Boyle took " a pretty large 

 piece of paper, which, being well moistened, and partly besmear'd 

 with our luciferous matter " was placed in a glass in the receiver of 

 the pneumatick pump. When " the pump was set awork," the light 

 seemed to increase but later became palpitating, and when air was 

 let in disappeared. This disappearance was attributed to the moist 

 air in the pump and it was found that on taking the paper out of the 

 receiver the light reappeared. Because of a belief that the vacuum 

 was not as good as could be obtained, both Boyle and the spectators 

 agreed the experiment should be repeated. 



The pamphlet on The Icy Noctiluca (1681) related that a liquid 

 noctiluca had been made since his book, The Aerial Noctiluca, had 

 been published and then explained that the word, glacial or icy, had 

 been chosen for the solid or consistent variety, because the small 

 transparent grains of material in the distillate looked like ice. They 

 did not shine under water but only in the air and smoke accom- 

 panied the luminescence. They were heavier than water, could be 

 melted under water and would fuse together to a large piece. The 

 water containing them had a penetrating vitriolic taste and on evapo- 

 ration left a gelatinous residue. Boyle studied the liquids in which 

 his icy noctiluca would dissolve, observing that in turpentine when 

 air was admitted, no light appeared above the bottle and no fumes 

 were observable. Because of the disagreeable smell of the noctiluca, 

 making experiments " much less acceptable, than they otherwise 

 would have been, to the delicate sort of spectators, especially to 

 ladies," Boyle " found a way to prevent this ungrateful concomitant 

 of our artificial light." 



His method was the use of an aromatical oil like cinnamon or 

 clove or mace, in which enough solution took place to make the 



* Perhaps an early notice of ozone production. 



