XIV 



SIMPLE CHEMICAL OPERATIONS 



211 



Separation of Solids. Filtration. We may also use the 

 solvent power of water to separate solids which are insoluble from 

 those which are soluble. 



EXPT. 202. Mix well together some fine sand and salt ; 

 place the mixture in a glass flask with sufficient water to dis- 

 solve the salt, and shake vigorously. Take a circular piece of 

 filter-paper and fold it in two, in the form of a semicircle, then 

 again to the form of a quadrant ; open out into the form of a 



Fio. 109. Filtration. 



hollow cone and fit it into a glass funnel (Fig. 109). Pour the 

 liquid through this filter and note that the solution of salt runs 

 through perfectly clear leaving the insoluble sand in the filter 

 paper. Evaporate off the water from the- salt solution and 

 obtain the salt. 



The above method of filtration is that which we usually adopt 

 in chemical operations when we wish to separate insoluble sus- 



v 2 



