240 Improved Apparafus for Tlltering and Sweetening 



an ifland which belongs to the lordfhip of Jever, and lies at 

 the diftance of a mile from Wangerland. J. J. Winckel- 

 mann fays, in his Oldenburg chronicle : " In the E. S. E. 

 near this ifland, oyfters were tranfplanted about twenty years 

 ago, and propagated, but they have been referved for the fo- 

 vereign lord." Winckelmann wrote about the end of the 

 laft century, but in what year I have not been able to learn. 



XI. Defcription of Mr. Collier's improved Apparatus for 

 Filtering and Sweetening Water and other Fluids. 



X HE importance of obtaining pure water for culinary 

 purpofes is fo obvious, that any invention for facilitating that 

 objefl deferves, and will be fure to meet with, due attention 

 from the public, as it is a matter that very much concerns 

 their health. 



The general praftice of paflling a fluid fimply through the 

 pores or interftices of any compaft fubftance is attended with 

 obvious objeftions. If the filter is either of animal or vege- 

 table production, it muft neceffarily be a6led upon by the 

 fluid, which at the fame time percolates through its own 

 fediment and corruption. Hence arifes the necefllty of fre- 

 quent change of the filter, which, while it does not alto- 

 gether remove the evil, is at the fame time attended with 

 much trouble and expence. If we ufe natural or artificial 

 ftone, or any other fubftance found in the mineral kingdom, 

 the fediment finds its way into the fubftance of the filler, 

 which is thereby rendered extremely foul, and cannot be 

 completely cleanfed by any contrivance hitherto reforted to 

 for that purpofe. In percolations through fand, or any thing 

 in the form of powder, this reafoning does not completely 

 apply ; but in that cafe the powder muft be often difplaced 

 to be waftied or changed. If unconfined, the fluid forms 

 channels for itfelf in various direftions; and if confined, a3 

 by mechanical force, in a ftrong box, it is liable to the very 

 objeftions urged againft the ufe of compa£l fubftances. The 

 inventor of the machines, of which it is now propofcd to give 

 fome account, does not pretend to have arrived at the ne plus 

 7 ultra 



