358 Scientific Intelligence. 



Our readers will remember that since M. Mitschcrlich's discovery of a 

 new selenic acid proportional to sulphuric acid, the term selenious acid is 

 applied to the acid discovered by Berzelius, and which consists of one 

 equivalent of selenium to two equivalents of oxygen, or it corresponds to 

 sulphurous acid. 



18. Bromine in the Water of the Baltic — This substance has been dis- 

 covered in the water of the Baltic by Dr Wohler and M. Kindt. (Pog- 

 gendorffy Ibid-) 



19. On a New Sulphate of Potash. By Mr R. Phillips. — The new salt 

 discovered by Mr Phillips is a sesquisulphate of potash, and was obtained 

 from the bisulphate of potash, formed in the process of preparing nitric 

 acid by the decomposition of one equivalent of nitre by two equivalents 

 of concentrated sulphuric acid. The following is the history and analysis 

 of the salt as given by. Mr R. Phillips in the Philosophical Magazine and 

 Annals for December 1827. 



" To the supersulphate of potash remaining in the retort, 1 added near- 

 ly an equal weight of water ; by the application of heat, the salt was readi- 

 ly dissolved, without ebullition, and consequently with but little dimi- 

 nution of the water. The salt obtained by the cooling of the solution con- 

 sisted of extremely minute filaments resembling asbestos in appearance ; 

 a part of the residual solution was so retained by the capillary attraction 

 of the crystals, that it could not be separated by draining, and it was ne- 

 cessary to absorb it by filtering paper. 



" The primary form of bisulphate of potash is either a right rhombic 

 prism, or an octahedron with a rhombic base, and the crystals are usually 

 so flat as to be tabular ; it appeared to be improbable that the acicular 

 crystals which I have now described, should be a variety of either of the 

 primary forms above-mentioned. I thought they might, however, he bisul- 

 phate of potash containing more or less than the two atoms of water, which 

 are known to exist in it in its common form. To determine this point I 

 made the following experiments : 100 grains of the filamentous salt, which 

 had been dried by exposure to the air in a moderately warm room, were 

 dissolved in water, and solution of muriate of barytes was added as long as 

 precipitation took place ; the sulphate of barytes after washing and ignit- 

 ing, taking the mean of two experiments, weighed 154.75 grains, equiva- 

 lent to 52.45 of sulphuric acid. 



To expel the water of crystallization, as well as the excess of acid, 100 

 grains of the filamentous salt were heated to redness in a platina crucible ; 

 the neutral sulphate of potash remaining weighed 78.4 grains, and con- 

 sequently 21.6 of sulphuric acid and water were expelled. Now as 88 of 

 sulphate of potash contain 40 of sulphuric acid, 78.4 contain 35.6, which 

 deducted from 52.45, the whole quantity contained in 100 grains of the 

 salt, leave 16.85 as the sulphuric acid expelled by heat, with 4.75 of water 

 of crystallization. It will be observed that the quantity of sulphuric acid 

 separated by heat from the supersulphate, is as near one-half that remain- 



3 



