^^ PURIFICATION or WATER. 



water with which the metropolis is fupplied contributes mate- 

 rially to the health and comfort of thofe who ufe it, and in fa<5l 

 renders it purer than almoft any known fpring water, a very 

 cheap and commodious apparatus for the purpofe may be con- 

 fidered as an obje6t of general utility. I therefore fend you a 

 fe'^ion of a machine whicli I conilru6led feveral years fince, 

 and which any common carpenter can make for a very few 

 fliillings, which may be thoroughly cleanfed at any time, dnd 

 jwhich occupies very little room. 



As you have already honoured feveral of my fhort eifays, 

 publithed in other colleftions, with infertion in your Journal, 

 you will, I truft, not be difpleafed that we (liould become im- 

 mediate correfpondents. 



I am. Sir, 



Your obedient Servant, 



H. C. ENGLEFIflLD. 



P.S. I will not anfwer for it that the machine I fend you 

 has not been already introduced into ufe. If it has, you will 

 of courfe fupprefs my letter; but if it has, ProfelTor Parrot's 

 filtre is quite nugatory. 

 Arrangement A molt excellent arrangement for the purification of river 



for purifying , water On a large fcale is mentioned in the writings of De Luc 

 fcaie, or De SautTure, but I cannot turn to the pafTage in their works. 



It was applied with complete fuccefs by the inventor, to the 

 ftream which fupplied a large town in Switzerland. The ma- 

 chine (if it may be fo called) was as follows: 



A is the upper furface of the flream to be purified, B the 

 bottom. Acifiern isfunkof fix or feven feet in depth, and of 

 a 43roper breadth, divided by parallel partitions, alternately 

 rifing above the furface level of the ftream and open at the bot- 

 tom, and level with the bed of the river, and clofed at the 

 bottom. It is obvious that the courfe of the water mufl be in 

 the dire(5lion of the arrows, and in this repeated and flow af- 

 cent and defceni, all floating impurities will be left at the top, 

 and the heavier mixtures will fubfide. The ciftern may be 

 eafily cleanfed, either by taking out the partitions, if it is on a 

 fmall fcale, or by fending perfons down between the walls, if 

 it is built permanently for a great ftream. Perhaps, indeed, 

 a box having the partitions filled half the way up with fand or 

 gravel, may on this plan be the bell of all liltres for domeftic 



J)efcnpHon 



