522 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



of wool, &c., iuto the nearest river. Such a tliiug could not happen in 

 England, where experience has taught people to utilize such refuse for 

 the manufacture of soap or gas, &c. It is therefore as great an advan- 

 tage to iudustrj^ as to the purification of the water not to let soapy water 

 flow into public water-courses. 



It maj^ justly be demanded of every manufacturer who uses large quan- 

 tities of water that he should pimfy the refuse water, and allow only such 

 water to flow into the river or brook which cannot do any harm. The 

 water used in working machinery should be kept apart from water whidli 

 in cleaning dyed substances absorbs the sui)erfluous coloring matter; 

 this last-mentioned water should be purified, while the former may safely 

 be allowed to flow into the river. 



It will also be advisable to see to it that not unnecessarily large quan- 

 tities of water are made impure ; this will be comparatively easy, as 

 a great deal of water may be saved by the modern improvements of our 

 machiner3\ 



In the above I have, of course, only given hints, which will have to 

 be specially adapted to every individual case, and which will only be 

 appreciated by competent persons. Here is another field of usefulness 

 for our inspectors of manufactures. 



JVb manufacturer should alloic refuse water containing free acid or free 

 alJcali toflotv into ptihlic water-courses ; such strong chemical substances 

 should at any rate first be changed to salts, which are far less injurious. 

 Lye may mostly be used again, especially if the first strong lye is at 

 once emjoloyed. 



The simplest, cheapest, and very generally used purifier is lime, em- 

 ployed either as quicklime or chalk. Mature employs lime and magne- 

 sia as purifiers of the soil. Organic substances combine with them ; 

 water containing iron loses it; and thus water penetrating the surface 

 soon becomes pure, containing only particles of the stratum through which 

 it has passed. The purifying effect of lime is still further heightened by 

 the circumstance that a large number of coloring substances enter into 

 insoluble combinations, not only with lime, but also with carbonated 

 lime. These combinations have long since been employed in the manu- 

 facture of coloring substances. The effect of the lime does by no means , 

 reach its end by its chemical combination with acids, but is continued 

 when the lime has assumed the form of carbonated lime. Lime is, there- 

 fore, the most effective purifier of all those waters which contain color- 

 ing matter. Lime likewise enters into insoluble combinations with al- 

 buminous substances, and therefore removes those substances which 

 chiefly cause putrefaction. Alum is frequently employed with the Ibne^ 

 but its addition should be entirely regulated by the local demand. 



Lime is used in the same kind of pits as mentioned above. The burnt 

 lime is placed in the first pit. As soon as the pit is filled with refuse 

 water it is stirred a few times, and the water will become clear in a very 

 short time, so that it frequently enters ^he second pit with but very 



