430 Col. Beaufoy's Astronomical Observations, [June, 



from half a cubic inch to a cubic inch or more. These, when in 

 use, may be immersed in a small iron cistern containing mercury, 

 and provided with a cover in which are two holes, one for the 

 tube, and the other for the stem of a thermometer, the degrees 

 of which are best engraved on the glass. The gas is, of course, 

 confined in the tube by keeping the open end immersed in a 

 small basin of mercury. 



By means of these improved modes of analysis, I have 

 already obtained some interesting illustrations of the nature of 

 the gases from coal and from oil. I reserve, however, the com- 

 munication of them, till I have had an opportunity of pursuing 

 the inquiry to a greater extent, and especially of satisfying 

 myself respecting the exact nature of the compound of charcoal 

 and hydrogen, discovered some years ago by Mr. Dalton, in oil 

 gas and coal gas, which agrees with defiant gas in being con- 

 densible by chlorine, but differs from it in affording more carbonic 

 acid and consuming more oxygen. 



Article IV. 



Astronomical Ohservatiovs, 1825. 

 By Col. Beaufoy, FRS. 



Bushey Heath, near Stanmore. 



Latitude 51° ST 44'3" North. Longitude West in time 1' 20'93". 



April 19. Emersion of Jupiter's first < Oh 34' 03 " I^Iean Time at Bushey. 



satellite ? 9 35 24 Mean Time at Greenwich. 



April 25. Ingress of Jupiter's third J 9 08 55 IMean Time at Bushey. 



satellite ( 9 10 16 INIean Time at Greenwich. 



April 30. Emersion of Jupiter's second ( 9 32 05 Mean Time at Bushey. 



satellite } 9 33 26 Mean Time at Greenwich. 



May 6. Emersion of Jupiter's third ( 11 53 20 Mean Time at Bushey. 



satellite ^U 54 41 Mean Time at Greenwich. 



April 24. Immersion of a small star hy ? j , gg j^.g ^.^^^.^-^ rj,.^^^ 

 the moon. ) 



Observed Transits of the Moon and Bloon-culminating Stars over the Middle Wire of 

 the Transit Instrument in Siderial Time. 



1825. Stars. Transit. 



April29.— 167 Virginis llh 42' 09-28" 



29.— Moon's First or West Limb II 55 07-57 



29.— 14 Virginis 12 10 24-17 



