160 M. Ossan on some Bodies which strongly absorb Light. 



phoric bodies, that have remained in darkness long after their 

 preparation, are not luminous. On being exposed for a minute 

 to the solar hght, they shine for a greater or less time ; Bologna 

 phosphorus for 4 minutes, that of arsenic S4 minutes, and phos- 

 phorus of antimony 149 minutes. At the end of this time, the 

 phosphorus of realgar was still as luminous as it was an hour be- 

 fore. After being exposed to red heat for several hours, and 

 then to light, the phosphorus of arsenic shone in the dark in 

 the same manner as before ; that of antimony had only a feeble 

 glow, and the phosphorus of realgar was destitute of light. 



If an electric spark be made to pass an inch above these dif- 

 ferent phosphori, they become luminous, with the same shades 

 of colours as if they had been exposed to the light. The phos- 

 phori reflect their light while exposed to the day ; but it is then 

 only a white light ; the coloured light is reflected only in the 

 dark. The light to which they are exposed during their prepa- 

 ration is not communicated to them, as they do not absorb light 

 at an elevated temperature. If they are only exposed to a feeble 

 light, they only acquire a slight phosphorescence. From all 

 these observations, the author admits, with M. Grotthus, that 

 there is a true absorption of light. Each phosphorus, accord- 

 ing to him, would have a certain capacity for that fluid. 



On the Modes of Preserving the bodies of Animals in Fluids of 

 different Kinds, particularly during Voyages and Travels. 



Immediately after the cessation of life, animal and vegetable 

 bodies are affected by an internal motion, named putrefaction, 

 which tends to separate and reduce to their original elements the 

 ingredients of which they are composed. Various methods have 

 been devised to prevent this process, among which immersion in 

 fluids is the most important. Of these fluids, the following are 

 those more commonly employed : 1. Aqueous fluids, instead of 

 preventing putrefaction, accelerate it ; and therefore can only be 

 used for washing the substances to be preserved previously to 

 their immersion in other fluids. Water in which alum is dis- 

 solved, has indeed a constringent effect upon the animal fibre. 



