52 
small quantities of water, the excess of calcium chloride is 
always found in the first solutions, whilst those following 
contain calcium and chlorine in the proportions correspond- 
ing to the empirical formula CaOCt This fact, however, 
only proves that bleaching powder is not a mixture of cal- 
cium chloride and hypochlorite, but that the bleaching 
compound contained in it has the Constitution which Pro- 
fessor Odling has assigned to it. 
Professor Williamson has shown that an aqueous solution 
of hypochlorous acid may also be obtained by suspending 
finely divided calcium carbonate in water and passing 
chlorine into the liquid until the carbonate is dissolved and 
then distilling the solution. In this reaction the compound 
Ca(OCl)Cl is probably also first formed and acted on by an 
excess of chlorine in the following way : — 
Ca I QQj + CI2 — I 
