Radiation of Non-luminous Heat 268 



provided the person is not exposed to the sun, the particular co- 

 lour of the clothing is not of real importance. 



If colour is not a determining quality, neither does roughness 

 appear to be so, for though generally the smooth surfaces are 

 lower on the list, this is not universal. 



The rough sulphate of baryta is lower on the list than the 

 smooth carbonate of lead. 



Plumbago occupies a low place, and India ink a comparative- 

 ly high one. 



The best radiators do not appear to belong to any particular 

 class of bodies ; litmus blue and Prussian blue are side by side, 

 while sulphuret of lead, and the bi-sulphuret of tin, are fifteen 

 numbers apart. 



If the results be admitted as decisive of the radiating powers 

 of the bodies used, they shew, that each substance has a specific 

 power not depending upon chemical composition nor upon co- 

 lour. I do not claim to found such a conclusion upon the ex- 

 periments ; their object has been before stated, and if they pre- 

 vent the introduction of an inference from an imperfect induc- 

 tion as a law of science, the labour bestowed upon them will be 

 amply recompensed. * 



Notes on the Natural History and Statistics of the Island of 

 Cerigo and its dependencies. By Robekt Jameson, Esq. 

 Assistant Surgeon, 10th Regiment of Foot, Corfu. 



Certgo is the most southern of the Ionian States. It is situ- 

 ated to the south of the Morea, at the mouth of the Gulf of 

 Kolokythi and Furnus, its nearest point to the mainland is only- 

 distant about twelve miles. The island is in shape triangular, 

 with its base towards the south. Its greatest length is about 

 nineteen and greatest breadth twelve miles; the whole island 

 forms an area of about 116 square miles. 



Under the denomination of dependencies are Cerigotto to the 

 S. S. E. distant about twenty miles, and several islets and rocks at 



• The scientific reader need not be reminded that these remarks do not 

 bear upon the radiation ct absorption of heat accompanying light. 



