Mr. Gr. W. Brown on Drift Weed Kelp from Orkney. 217 



chloride of palladium. The iodide of palladium being separated by fil- 

 tration, the excess of palladium was removed from the filtrate by sul- 

 phohydret of ammonia. It was found in this experiment that sulpho- 

 hydret of ammonia answered better than sulphohydric acid for removing 

 the excess of palladium ; because, when sulphohydric acid is employed, 

 part of the sulphuret of palladium is dissolved by the acid, which was 

 previously united to the palladium, which was set free by the sulpho- 

 hydric acid. Having removed the excess of sulphohydret of ammonia 

 by boiling, chlorine was again passed through the solution to decompose 

 bromide. The bromine which was set free was taken up by ether (this 

 had a yellow colour, probably from the presence of a small quantity of 

 bromine). The ethereal solution was then neutralized by soda, evaporated 

 to dryness, and heated to redness. The aqueous solution of the residue 

 gave a white precipitate with nitrate of silver, which consisted principally 

 of chloride of silver. But from the colour of the ether, it was evident 

 that it contained a small quantity of bromine. 



Estimation of Potassium. — To determine accurately the quantity of 

 potash, it was considered advisable to convert any potash that might exist 

 as sulphate into chloride, which was efiected in the following manner. 

 From the solution of the salts, the sulphuric acid was precipitated by 

 chloride of barium and the sulphate of barytes, separated by filtration. The 

 excess of barytes was then thrown down by carbonate of ammonia. The 

 liquor, after the carbonate of barytes had been removed, was evaporated 

 to dryness, and heated to redness to expel the ammonia. The residue 

 was dissolved in water, and the potassium precipitated by the addition of 

 the sodium bichloride of platinum, as the potassium bichloride of platinum 

 (KCl Pt CI2). 



(KCl Pt CI2) Potassium. Potassium, per cent. 



30 grains gave 310 ... 5071 ... 10- 



Estimation of Lime. — This was determined by precipitation as oxalate 

 of lime ; the precipitate, when heated, was converted into carbonate of 

 lime. 



Carlionate of Lime. Lime. Lime, per cent. 



400 grains gave 1-49 ... -805 ... -201 



500 " " 2-38 ... 1800 ... -260 



Mean lime per cent 230 



Estimation of Magnesia. — The magnesia was precipitated from the 

 solution of the salts, by phospiiute of soda and ammonia, as ammonia 

 phosphate of magnesia, which was converted, by heat, into the diphos- 

 phate of magnesia. 



Dipliospliate of Magnesia. Magnesia. Magnesia, per cent. 



500 grains gave 3-61 ... 1-821 ... "264 



400 " " 300 ... 1071 ... -267 



Mean mngncsia, per cent '277 



