DR. WALL. 469 



against paper, and saw the sheet ''become lurid like a glow 

 worm." l 



In 1708, Dr. Wall, 2 who evidently disagreed with 

 Hauksbee's conclusions as to the electric nature of the 

 barometer light, evolved a hypothesis concerning the 

 amber about as odd as that which Father Grandamicus 

 had proposed to account for the earth's rotation. Gran- 

 damicus said that the earth does not rotate because it is a 

 magnet, and Wall asserts that the amber attracts, not be- 

 cause of its electrical quality, but because it is "a natural 

 phosphorus, a mineral oleosum coagulated with a mineral 

 acid of spirit of salt." Wall, however, attains immortality 

 neither for his theories nor for his experiments, but for 

 an expression. Hauksbee, long before, had heard the 

 crackles and had likened the fires in his glass globe to 

 flashes of lightning. Wall, rubbing a large piece of amber 

 and seeing the sparks and hearing the noise, however, 

 says: u Now I doubt not, but on using a longer and larger 

 piece of amber, both the cracklings and light would be 

 much greater, because I have never yet found any crack- 

 ling from the head of my cane, though it is a pretty large 

 one: and it seems in some degree to resemble Thunder and 

 Lightning." It is a pity that Wall's far-fetched notion 

 that the amber is phosphorus, and its light that of phos- 

 phorus, should cast a shadow on his title to being the first 

 who saw in the electric spark and detonations the effects 

 of Jove's armory in miniature. 



Bernouilli, to whom Frederick of Prussia, on the recom- 

 mendation of Leibnitz, then President of the Berlin 

 Academy of Sciences, had presented a gold medal, worth 

 forty ducats, as a reward for his discovery, denied Hauks- 

 bee's explanation of the mercury light. It is needless to 

 review his contentions; they went the way of the learned 

 arguments whereby the Italian ecclesiastics in Galileo's 

 time sought to eliminate the moons of Jupiter. 



The progress of electrical discovery had now reached one 



Optics. Q. 8. 2 Phil. Trans;, No. 314, p. 69, 1708. 



