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THE POPULAR SCIENCE MONTHLY.
tained in treating the natural waters. One or two hundred grammes (three and a half to seven ounces) of tilled earth mixed with a pint of
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/22/PSM_V19_D252_Crystals_of_iodoform_obtained_with_rain_water.jpg/440px-PSM_V19_D252_Crystals_of_iodoform_obtained_with_rain_water.jpg)
Fig. 3.—Crystals of Iodoform obtained with Rain-water.
water gave a similar precipitate of iodoform when distilled and exposed to the reactions employed in the other experiments. The precipitation
![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/86/PSM_V19_D252_Crystals_of_iodoform_obtained_with_snow_water.jpg/440px-PSM_V19_D252_Crystals_of_iodoform_obtained_with_snow_water.jpg)
Fig. 4.—Crystals of Iodoform obtained with Snow-water.
of iodoform by the addition of iodine and carbonate of soda is a very evident test of the presence of alcohol. Iodoform