1824.J Col. Beaufoy's Astrommical Observations. 141 



cipitate, constituting 06 of the weight of the stone, and com- 

 posed of 0*47 fluate of lime, 0*07 of the phosphates of lime and 

 alumina, and 0-06 of oxide of iron. The ammoniacal liquid, on 

 being concentrated, deposited an additional quantity of the fluo- 

 silicate of potash, but the difficulty of washing it prevented me 

 from ascertaining its weight. 



3. The white compact variety resembling magnesite does not 

 contain a trace of magnesia, agreeing, in this respect, with all 

 the other varieties of the sprudelstone. The carbonate of 

 strontian also, and the earthy fluates and phosphates, exist in it 

 in the usual proportion. 



4. A very peculiar variety of sprudelstone, which is formed 

 by the combined action of oxidation and evaporation, was found 

 to be composed of 



Carbonate of lime 43-20 



Subphosphate of peroxide of iron .... 1*77 



Peroxide of iron 19*35 



Carbonate of protoxide of iron 12*13 



Phosphate of alumina 0*60 



Silica 3*95 



Water 9*00 



100*00* 



Article XIV. 



Astronomical Observations, 1824. 

 By Col. Beaufoy, FRS. 



Bushey Heath, near Stanmore. 



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



Moon eclipsed. 

 T , ,„ „ . . Ujk 20' IS" Mean Time at Bushey. 



July 10. Beginning j, 5 3Q 39 Mean Time at Greenwich. 



Article XV. 



Reply to an erroneous Statement respecting Sir Humphry Davy's 

 Method of defending the Copper Sheeting for Ships' Bottoms. 



Since Sir Humphry Davy's paper (see p. 94) was printed, the 

 32d number of a weekly publication, called the Mechanic's 



• The sum of these quantities (correctly copied from the original) i» only 90. 

 Should the carbonate of lime be 53*2 ?—Edit. 



