166 BLEACHING. 



the lime, and form oxymuriate of lime ; but as the 

 water can only retain a small portion of lime, this 

 was not found of much use. To cause a larger 

 quantity of lime to combine with the oxymuriatic 

 acid gas, the lime is mechanically suspended by 

 agitation in the water into which the gas is made 

 to pass, so as to present fresh matter to the gas. 

 By this means, the oxymuriatic acid combines with 

 the lime, forming a compound soluble in the 

 water : this is used as a bleaching-liquor. 



The oxygenated muriatic acid gas may also be 

 combined with lime in a dry state. To effect this, 

 the oxymuriatic acid gas is sent into a vessel contain- 

 ing dry hydrate of lime (that is, lime slacked with 

 water) : the powder is agitated, and the gas com- 

 bines with it to a certain amount, or till the hy- 

 drate of lime becomes saturated. The compound 

 is a soft white powder, possessing little smell. It 

 is partially soluble in water, yielding a solution 

 much the same as that obtained by the former 

 process. 



Although most salts that are soluble in water 

 are capable of being formed again by evaporating 

 the water, either in crystals or in a dry saline mass, 

 this is not the case with oxymuriate of lime. When- 

 ever a solution of it is evaporated, part of the acid 

 escapes, and the rest is mostly converted into mu- 

 riatic acid ; so that instead of oxymuriate of lime, 

 muriate of lime is obtained. Hence the dry salt 

 cannot be obtained from the liquid solution. 



The dry oxymuriate of lime may be very con- 

 veniently transported without injury, an advantage 

 not possessed by the acid alone, which cannot be 

 transported without the loss of almost half its 

 strength : but it must be observed that the dry 

 salt is much impaired by being long kept. 



