J. E. MAYER) ESQ. ON THE WATER 



noted below. The nitrates were then separately evaporated, 

 and the residues left weighed and set down opposite the 

 filtering material used. These various residues were then 

 ignited, and the respective residues again weighed are set 

 down in order — the loss in each case being the organic matter. 

 The figures thus obtained by being respectively deducted 

 from the amounts originally present, shewed by the differ- 

 ence how much had been separated by each filter material. 



Total impurity present previous to filtration 15*08 grains, 

 i. e. } in the gallon 241*28 grains. This total represent 

 organic and inorganic impurity. 



Residue left after ignition found equal to 12*52 grains? 

 i. e. } in the gallon 200*32 grains. 



Difference, i. e. y organic matters burnt off, equal 2*56 

 grains, or, calculated on the gallon, equal 4046 grains (^HT 

 Vide note.) 



A 



Material Used for 

 Filtration. 



B 



C 



D 



E 



F 



G 



Total left after eva- 

 porating filtrate. 



Residue left after 

 ignitiou of B. 



Difference B and C. 



Organic matter sep- 

 arated by each agent, 

 i. e., difference be- 

 tween D and original 

 amount present. 



Percentage amount 

 separated 



A mount separated by 

 each filter calculated 

 on the Imperial Gal- 

 Ion. 







Grains. 



Grains 









1 . Ordinary filter paper 



14-69 



12-36 



2-33 



•23 



8-98 



3-68 



2. Swedish filter paper 



13-87 



12-24 



1-63 



•93 



36-36 



14-88 



3. Clean white sand 



15-14 



13-09 



2-05 



•51 



19'19 



8-16 



4. Sand and Charcoal 



14-93 



12-94- 



1-99 



♦57 



22-35 



9-12 



5. Natural Magnetic Oxide of 















Iron 



14-18 



12-49 



1-69 



•87 



34-00 



13-92 



6. Artificial Magnetic Oxide of 















Iron 



14-14 



12-50 



1*64 



•92 



36-00 



14-72 



7. Einely divided mica or tale... 



14-22 



12-39 



1-83 



•73 



28-51 



11-68 



8. Swedish paper and Magnetic 















Oxide of Iron 



13-99 



12-37 



1-62 



•94 



37* 



15-04 



9. Swedish paper, Magnetic 









•95 



nearly. 



15-20 



Oxide of Irou 



13-91 



12-33 



1-61 



37-10 



Column F has been inserted for the sake of the compari- 

 son which can thus be made between the results here set 



down and those obtained by other experimenters, who have 



