92 Intelligence and Miscellaneous Articles. 



Some further details on this subject, and an account of the che- 

 mical processes employed, I reserve for a paper which I intend to lay 

 before the Royal Society. 



I am, &c. &c. 



Lacock Abbey, Feb. 19, 1841, H. F. Talbot. 



PROCESS FOR OBTAINING THE HYDROBROMIC AND HYDRIODIC 

 ACIDS. BY DR. R. M. GLOVER. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



In the latest Report of the British Association, there is an ac- 

 count of a new process for obtaining hydrobromic and hydriodic 

 acids, said to be communicated by me. This account is quite incor- 

 rect. I first observed this erroneous report in the Athenaeum, whence 

 its was copied into several British and Foreign journals ; but as I 

 gave a correct abstract to Dr. Playfair, one of the Secretaries to the 

 Chemical Section, when he passed through this town shortly after the 

 meeting, I expected to see the error corrected in the Report of the 

 Association. 



It is known that all the solid bromides and iodides are decomposed 

 by sulphuric acid with evolution of bromine and iodine ; but I find 

 that although the solid bromide and iodide of barium obey the ge- 

 neral rule, their solutions are decomposed by sulphuric acid without 

 any evolution of the elements, and with the formation of pure solu- 

 tions of the hydracids. This difference is doubtless owing to the 

 agency of the water in speedily removing the sulphuric acid in the 

 form of the insoluble sulphate. The Report of the Association incor- 

 rectly states that I had proposed the solid iodide and bromide of 

 barium acted on by sulphuric acid as convenient sources of the hy- 

 dracids. My process is the very reverse. 



In this way, in particular, hydrobromic acid can be conveniently 

 obtained ; more conveniently indeed than the hydriodic acid ; be- 

 cause it is difficult to prepare the iodide of barium unmixed with 

 the carbonate of baryta and free iodine, while the bromide does not 

 undergo any decomposition from the carbonic acid of the atmosphere. 

 A saturated solution of the bromide may be decomposed by a solu- 

 tion of sulphuric acid diluted with an equal bulk of water, the di- 

 luted acid being allowed to cool before it is added to the saline solu- 

 tion, and hydrobromic acid is set free unmixed with bromine. In 

 this way the amount of the hydracid in any solution of it we may 

 employ can be easily known, calculating from the weight of the bro- 

 mide decomposed. 



Should you insert this rectification, you will oblige 



Your obedient Servant, 



Robert Mortimer Glover, M.D., 

 Lecturer on Chemistry in the Newcastle 

 School of Medicine. 

 Literary and Philosophical Society Rooms, 

 Newcastle, April 21, 1841. 



