f 43 ) 



" A friend of mine, fays the Dodor, in this 

 town [Newcaftle] has a ciflern for colledling 

 rain water, fo conftru^led, that it both allows the 

 water to fubfide, and the upper part of it to run 

 through a bed of fand, which is raifed by a parti- 

 tion above the bottom of the ciftern ; by which 

 means the water becomes perfe6lly clear and 

 bright, and is preferred by mod who have tafted 

 it, to any other water in this tov/n'*. 



4. Some have obje6led, but probably without 

 reafon, to this mode of filtration, on a prefump- 

 tion, that the fand has the fame effed on the wa- 

 ter as the filtering Rone : for it is faid, that the 

 fand is infenfibly difTolved by the water ; {o that 

 In four or five years it will have lofl a fifth part of 

 its weight. M. Amy therefore recommends 

 the filtration of water through a fpunge, more or 

 lefs comprefTed. And this, he afTures us, will 

 render it, not only more clear, but more whole- 

 fome, than either a Hone or fand, 



5. As the pureft of all water is obtained by 

 diflillation. Dr. Heberden recommends this me- 

 thod, as particularly ufeful where fuel is cheap 



F 2 and 



