Mr. G. W. Brown on Drift Weed Kelp from Orkney. 215 



water and weighed. The difference between the weight of this precipi 

 tate and that of the sulphate of barytes, previously obtained, indicated 

 the amount of sulphate of barytes formed by the action of the nitric acid 

 on the sulphite. From this the sulphurous acid was calculated — 



Sulphate of Snlphuric Sulphuric Acid Difference Sulphurous 



Barytes. Acid. before obtained. Acid. 



100 gave 15-75 ... 5-40 ... 4-915 ... -485 ... '392 

 Estimalion of Hypo-sulphurous Acid. — The soluble salts being sepa- 

 rated, by means of cold water, from the insoluble salts ; the sulphurets 

 and carbonates were removed by sulphate of copper. After separating 

 this precipitate by filtration, sulphuric acid was added to the liquid, 

 which decomposed the hypo-sulphites, sulphurous acid being evolved and 

 sulphur precipitated. This sulphur was then washed, dried at 212° F., 

 and weighed. 



„ , , ,, , , , . , Hypo-sulphurous Acid, 



Sulphur. Hypo-sulphurous Acid. "^ Per Cent. 



400 grains gave -18 = '54 ... '115 



Estimation of Svlphur. — The quantity of sulphur in the soluble salts 

 was estimated by deflagrating a portion of the kelp with nitre. By this 

 process all the sulphites, hypo-sulphites, and sulphurets, were converted 

 into sulphates. The sulphuric acid was then precipitated by chloride of 

 barium as sulphate of barytes, which was weighed, and the sulphuric 

 acid contained in it calculated. It is obvious that the sulphuric acid 

 thus obtained, comprehended all the sulphur existing as sulphurets and 

 sulphur acids in the original kelp. If we subtract from it the sulphuric 

 acid found to exist, as such, in the kelp, we have remaining the sulphuric 

 acid equivalent to the sulphites, hypo-sulphites, and sulphurets in the 

 kelp. If, again, we subtract from the last result the calculated quantity 

 of sulphuric acid equivalent to the sulphurous, hypo-sulphurous acid, and 

 the sulphuret of the insoluble salts, the remainder will be the sulphuric 

 acid equivalent to the sulphur of the soluble salts. 



Sulphate of Barytes. Sulphuric Acid. ^"'^e" cenf'^"'' 



200 grains gave 4655 16-04 8-02 



Original sulphuric acid, 4-92 



Sulphuric acid = Sulphurous acid, -490 ... 3-10 



— — = Hypo-sulphurous acid, -191 



— — = Sulphur of insoluble salts,.. -965 



Total calculated sulphuric acid, 1.446 



Sulphuric acid =^ Sulphur of soluble salts, 1-654 



Sulphur, soluble salts, per cent., -6616 



Estimalion of PhospJioric Acid. — To the solution from which the sul- 

 phuric acid had been precipitated, by chloride of barium and muriatic 

 acid, after separation of the precipitate, ammonia was added, when phos. 

 pbate of barytes fell. 



I'liospliatc of riiospliorlc I'liosplioric Acid, 



Barytes. Acid. pci- cent. 



200 grains gave .... 202 -649 -3245 



