THE 



c 40 SerpentU. 44 Bootis. 



3/ Leonis. S Serpentis. 



Librae Prae. t Eootis. 



70 Opliiuchi. 05 Herculis. 



Herculis. ft Serpentis. 



Corona?. /* Herculis. 



| Bootis. 2> Herculis. 



Performance of different telescopes. 



Dr Kitchiner has seen the small star accompanying Polaris Avith a 

 feet achromatic, aperture If inches; and the small star accompanying- 

 Rigel; but the telescope was exquisitely perfect. 



t Bootis, Herculis, y Andromeda, Cygni, Aquarii, Pole Star, 

 Castor, Rigd, maybe seen with a fine 44 inch achromatic, ofvf aper- 

 ture ; but not one instrument in a hundred will shew them without a 

 falsa light round the larger star. 



With an exquisite achromatic of 46 inches focus and a treble object 

 glass of SB inches aperture, Dr Kite-Inner has seen the Pole star with the 

 fallowing powers, 40, 80, 150, 250, S50, 4s 0, TOO, and even with 1 1>3 times 

 the small star was still visible. This shews only how far magnifying 

 power could be carried with this instrument, as it was with evident de- 

 triment to vision when higher than 80. 



With a most perfect achromatic of 44 inches focus, aperture f indies 

 made by Dolload, Mr Walker made the following observations. With a 

 negative power of ISO, he-saw t Bootis double j t Bootis ; ?j Coronse Bo- 

 realis. Three satellites of Saturn ; the shadow of his ring on the planet ; 

 and a beltj d Serpentis j Herculis; the Pole star; / Bootis, and/i Dra- 

 conis ; powers 453 single eye glass, and ISO, and 133 negative powers, 

 Rigd with 133, and the star in Monoceros' right foot treble with powers 

 0,180, and 4*3. 



Tfce ordinary powers used by Messrs South and Herschel, (tee Phil. 

 Trans.) in forming their catalogue of double stars, was 179; though oc- 

 casionally a lower power of 105, and a higher one of 273 were also used. 



TEMPERATURE of Atmosphere. See Atmosphere. 



THERMOMETER. Freezing point. Soiling point. 



Fahrenheit's Thermometer 32 212 



Reaumur's do. 80 



Ccntrigrsde do ..,. . 100 



503 



