328 Col. Beaufoy's Astronomical Observations. [May, 



some definite criteria by which the nature of heating agents may 

 be distinguished and compared ; and instead of framing theories 

 to explain the union of heat and light in the sun's beams, to 

 describe the nature of the phenomena in conformity to the 

 criteria above pointed out, as afforded by certain experimental 

 facts. 



It becomes necessary to subject to an examination by those 

 criteria the supposed exterior heating effect of the prismatic 

 spectrum ; as well as the analogous exterior heat of the cone of 

 light formed by a lens, and probably several other phenomena, 

 before we can obtain from them any further information respect- 

 ing the nature of the heating power which is so inseparably 

 associated with the sun's light. 



The remarks hitherto made apply to the subject of solar light 

 and heat; but they might be extended also to the investigation 

 of the relations of light and heat from terrestrial sources. The 

 want of some fixed criteria of definition must upon consideration 

 be felt equally in following up this part of the subject as in the 

 former ; and to endeavour to supply that want should be the 

 first business of the experimenter. 



Some further observations will probably form the subject of a 

 future communication. 



Article II. 



Astronomical Observations, 1824. 

 By Col. Beaufoy, FRS. 



Bushey Heath, near Stanmore. 



Latitude 51° 37' 44-3" North. Longitude AVest in time 1' 20'93". 



March 28. Emersion of Jupiter's second < 8h 17' 24" Mean Time at Bushey. 



satellite J 8 IS 45 Mean Time at Greenwich. 



March 31. Emersion of Jupiter's first < 8 13 49 Mean Time at Bushey. 



satellite } 8 15 10 Mean Time at Greenwich. 



"12 15 44 Immersion of a small star. 



12 19 01 Im. Jupiter's 4th satellite. 



12 21 19 Immersion of a small star. 



13 21 51 Em. Jupiter's 1st limb. 

 J3 22 01 Em. Jupiter's 2d limb. 



Clouds prevented the Immersion of Jupiter being seen: at the Emersion, the limbs of 

 Jupiter, and the Moon, were tremulous. 



April 7. Emersion of Jupiter's first ( 10 09 15 Mean Time at Bushey. 



satellite }\0 10 36 Mean Time at Greenwich. 



April 5. Occultations by the moon, Si- 

 derial Time 



