1825.] Col. Beaujoy's Astronomical Observations. 131 



silicated fluoric acid is volatilized ; neither do we obtain the 

 compound by evaporating the acid solution to dryness because 

 when a solution of fluor spar and silica in an excess of muriatic 

 acid is evaporated, there remains nothing except muriate of lime. 

 The double sihcated salts of those bases from which ammonia 

 separates a portion of their fluoric acid would probably give 

 precipitates with that alkali, in which a different relation would 

 exist between the proportions of the sihcate and fluate. 



{To be continuea.) 



Article VII. 



Astronomical Observations, 1824 and 1825. 



By Col. Beaufoy, FRS. 



Biishey Heath, near Stanmore. 



Latitude 51° 3T 44*3" North. Longitude West in time 1' 20'9S". 



6^^1*6. Immersion of Jupiter's first (1 Oh 0' 25" xMean Time at Bushey. 

 jjec. lo. xu ^^^^^.^^ r ^j^ Pj ^g Mean Tmie at Greenwich. 



jln!%. Immersion of Jupiter's tliird U2 ST 01 Mean Time at Bushey. 



sateUite •• • iJ2 38 2-2 Mean Tmie at Greenwich. 



Jan. 8. Immersion "of "jupi'ter's first UO 09 16 Mean Time at Bushey 



satelhte ^ 10 10 37 Mean Time at Greenwich. 



Ja". 11. Immersion'of' Jupiter's third (16 35 19 Mean Thne at Bushey 



satellite • i^^ 36 40 Mean Time at Greenwich. 



Occultation by the Moon. 

 Dec. 31. Immersion of § Pisces 6h 26' 46" Siderial Time. 



Francis Baily, Esq. having favoured me with the new method 

 of determining the longitude by the culmination of the moon and 

 stars ; together with a list of stars applicable to the purpose for 

 the year 1825, the following observations were made at Bushey 

 Heath : — „. , . , m- 



Transit over the Middle Wire in Siderial Time. 



(IGemini 6h 53' 46-46" 



JMI. 4. \ Moon's First Limb 7 08-93 



[c, Gemini ' 11 ''O'a 



Article VIII. 

 On a peculiar Class of Combinations. By Dr. F. Wohler.* 



With the intention of preparing cyanuret of silver by the 

 ciprbcal decomposition of cyanuret of mercury and nitrate of 



• Annalen der Physik. 

 K 2 



