286 History of Luminescence 



Cromwell Mortimer, M, D., Secretary of the Royal Society, was 

 much impressed by the electrical experiments shown at the Royal 

 Society meetings and by the accounts of spontaneous human com- 

 bustion recently reported by Paul Rolli (1745) in the Phil. Trans. 

 Imbued with the idea that there are " Elements of Fire and of Air 

 lying dormant in all Bodies," particularly " animal Sulphur, com- 

 monly called by our modern Chemists, Phosphorus," Dr. Mortimer 

 (1745) cited fireflies, luminous fish, light from friction of the hair 

 of animals as examples. He also sounded a word of caution: 



Animals appearing more susceptible of electric Fire than other Bodies, 

 greatly confirms my Conjectures of the phosphoreal Principles; and I 

 should think, that being render'd electric to any high Degree might 

 prove a dangerous Experiment to a Person habituated to a plentiful Use 

 of spirituous Liquors, or to Embrocations with camphorated Spirit of 

 Wine; on the contrary, in some languid, cold, or wornout Constitutions, 

 possibly, future Experiments may evince, that Electricity may be used 

 medically in order to renew and regenerate a proper Quantity of vital 

 Fire, such as is necessary for the conveniently carrying on, and perform- 

 ing the animal Functions. 



Sporadic observations on the true electric light were made in 

 various places. Gottfried Heinrich Grummert (1719-1776) of Biala, 

 Poland, later of Dresden, discovered (1745) that an exhaused glass 

 tube did not need to be rubbed to show the electric light but would 

 glow if touched to or merely brought near an electrified conductor. 

 He also observed that for some time afterwards light might appear 

 spontaneously in the tube at a distance from an electrified body. 

 Grummert suggested the use of such a tube in mines, where a light 

 from fire cannot be used because of the danger of explosions. 



Discovery of a condenser, the Leyden phial, independently by 

 Bishop G. von Kleist in 1745 and P. van Musschenbroek in 1746, 

 gave a great impetus to electrical study, although attention was 

 diverted for the moment from electroluminescence to spark dis- 

 charges. The shocks which could be transmitted to subjects became 

 terrific and really dangerous. All students of electrical history are 

 familiar with the famous statement of Professor Musschenbroek in a 

 letter to M. Reaumur of the French Academy, that he would not 

 take a second shock from the electric phial for the Kingdom of 

 France. 



The Abbe Jean Antoine Nollet (1700-1770) was one of the first 

 to be informed of the Leyden discovery, and was especially active 

 in charging and shocking animals and persons. Most of the work 

 was carried out in the air and the value of points for brush dis- 

 charges became well recognized. Franklin, in a letter to Peter Col- 



