248 THE POPULAR SCIENCE MONTHLY. 



prevention of putrefaction and fermentation of certain liquids. It is 

 with this view that the interiors of barrels intended to hold wine, beer, 

 or water, are carbonized. Certain odorous culinary operations are ren- 

 dered inodorous by the introduction of a fragment of charcoal into 

 the i^ot. The efficacy of charcoal as a filtering material is due in a 

 great measure to the oxidizing action of the oxygen contained in its 

 pores." 



In the article on vegetable charcoal in the "National Dispensatory," 

 the writer says : " The most fetid gases disengaged by putrefaction 

 are among those which are the most abundantly absorbed by charcoal, 

 viz., ammonia, sulphureted hydrogen, and sulphurous acid, and the 

 oxygen contained in the charcoal combines with the other deleterious 

 substances and generates new and inodorous compounds." Buck says, 

 " All varieties of carbon formed by the destructive distillation of vege- 

 table or animal matter possess the property of removing organic matter 

 from solution." Fowne's " Chemistry" says of charcoal, "It is said to 

 absorb ninety times its volume of ammonical gas." But sufficient author- 

 ities have been quoted to prove the high estimate in which vegetable 

 charcoal is held as a filtering material by chemists and sanitarians. 

 Careful experimenting with it has satisfied me of its efficacy and prac- 

 ticability. It is efficient, clean, easily obtained by any one, and so 

 cheap that after a few weeks' use it can be thrown away, and a clean 

 supply substituted, and the cost need not be taken into consideration. 

 Animal charcoal possesses valuable filtering properties, but it is very 

 expensive, difficult to be obtained, and is so associated in the minds of 

 the people with dead horses and the bone-yard that a strong prejudice 

 exists against it. I have thus tried to show in this paper — 1. That 

 clean drinking-water is essential to health. 2. Some of the well-estab- 

 lished results of drinking polluted water. 3. The various filtering ma- 

 terials that have been used, with their merits and objections. 4. The 

 superiority and availability of vegetable charcoal as a filtering mate- 

 rial. 



In conclusion, in answering the question, " How, then, may we obtain 

 clean drinking-water?" I would answer, by filtering the water slowly 

 through properly adjusted vegetable charcoal placed in an earthen re- 

 ceptacle of some kind so that the water will not come in contact at 

 any stage of its passage through the filter with metal of any kind. 

 Cool the filtered water by placing ice under or around the vessel in 

 which the water is contained, but do not put the ice into the water, 

 or its impurities will be liberated by melting and contaminate it. Act- 

 ing on these suggestions, I believe clean drinking-water may be ob- 

 tained in any family, and, with clean water, less sickness. 



