OBSERVATIONS ON SPONTANEOUS LIGHT. 107 



mixture, the temperature of the laboratory would commonly 

 foon revive the light, which rendered the experiments not al- 

 together fatisfactory. Finding it thus fomewhat difficult to 

 extinguifh folar light in air, recourfe was had to water, in the 

 manner above described. This anfwered perfectly well ; for 

 the water, when frozen, gave a fubftantial body, as it were, 

 to the imbibed light of the phofphorus, lb as to enable it to 

 retain the excefs of cold anting from the frigorific mixture; 

 thereby making the experiments quite fatisfactory. When the 

 phofphorus was thus furrounded by ice, only a few minutes 

 ftay in the frigorific mixture would generally be fufficient for 

 a total extinction. 



OBSERVATION. 



From thefe experiments, compared with thofe recited in my 

 former Paper on fpontaneous light, it appears that folar light, 

 when imbibed by Canton's phofphorus, is fubjeel to the fame 

 laws, with refpect to heat and cold, as the fpontaneous light 

 of fifhes, rotten wood, and glow-worms. 



P. S. In thefe experiments with folar light, the phofphorus 

 was fometimes expofed to the direct rays of the fun, at other 

 times to common day-light, in a northern afpect ; and it was 

 remarked, that it became fomewhat more luminous by mere 

 day-light, than by the rays of the fun. 



It may alfo be proper to obferve, that the above experi- Improved pre* 

 ments were made with an improved preparation of Canton's P aratl °" of Can* 



. . r r l ton s pholpho- 



pholphorus. This improvement, which was firft made by Dr. rus by Dr. Hig- 

 Higgins, confiits in omitting the pulverization of the (hells. S ins * 

 His method was, after calcining the oyfter-fhells, to put the 

 pieces, both great and fmall, in layers, into a crucible finv 

 nifhed with a cover, and to fprinkle flowers of ful phur between 

 each layer. After they had remained fome time in the fur- 

 nace, they were taken out, fuffered to cool, and then kept in 

 a large bottle with aglafs ftopple. For this communication, I 

 am indebted to Mr. Lewis of Holborn, near Southampton- Dark room of 

 ftreet, who has an extraordinary dark room, where, at times, Mr * *-* ewis » 

 he amufes his friends with fome beautiful appearances, arifing 

 from folar light imbibed by phofphorus prepared as above di- 

 rected. A ltill further improvement of this phofphorus, it 

 appears to me, may be made by fubllituting precipitated ful- 

 phur for the flowers of fulphur ; and the experiments of this 

 feftipn were chiefly made with phofphorus fo prepared. 



X. Defcription 



