226 Mr. Williamson on the 



stilled over unchangetl. The so-called oxychlorides, when 

 similarly treated, behave in the same manner. 



The process in these instances is extremely simple, if we 

 only recollect that hypochiorous acid with hydrochloric sets 

 chlorine free by forming water; or, which is the same thing, 

 the metal of the chloride deoxidates the hypochiorous acid in 

 order to be able to combine as oxide with sulphuric acid, 

 while from both the chlorine is set free. 



In the second instance the salt of hypochiorous acid is alone 

 decomposed, while no excess of sulphuric acid is present to 

 cause a decomposition of the chloride. 



Now if these oxychlorides were simple combinations of 

 chlorine with oxide, the first drop of sulphuric acid would set 

 free chlorine. 



Founded on the correctness of this view, this great chemist 

 has given us a method of preparing hypochiorous acid, far 

 more practical than that formerly used. He distils the so- 

 called chloride of lime with dilute nitric acid, which must be 

 very carefully added in the manner above described, and di- 

 stils off the hypochiorous acid. He confirms Balard's state- 

 ment of its composition. Hypochiorous acid possesses, ac- 

 cording to Gay-Lussac, the following properties : — It is a 

 feeble acid, weaker perhaps than carbonic, although they 

 mutually expel one another from their salts. Its salts have 

 a great inclination to decompose into chlorides and chlorates. 

 These salts, as such, possess no bleaching properties. In or- 

 der to give a bleaching reaction, they must be decomposed by 

 a stronger acid. They are partly decomposed by chlorine. 

 Hypochiorous acid can be distilled over from any of these 

 salts after treating it with chlorine. 



I will now communicate some experiments which I have 

 made on the action of chlorine on bases, and the products of 

 this action. My principal object during these experiments 

 was to become better acquainted with the manner of the for- 

 mation, with the properties and decompositions of this most 

 interesting compound, hypochiorous acid. 



The experiments were performed in the laboratory at Gies- 

 sen, and I had, during the course of them, the advantage of 

 the presence and counsel of Professor Liebig. 



The first point which I endeavoured to ascertain was the 

 quantity of chlorine with which a base is capable of combining. 

 Barytes was first subjected to this examination. A concen- 

 trated solution of this earth was saturated with chlorine by 

 conducting a stream of the gas, which had been washed by 

 water, slowly into it. This process was not considered com- 

 plete until the liquid had assumed a strong colouring of chlo- 



