. Annual report of the Agricultural Experiment Station. Cornell University. Agricultural Experiment Station; Agriculture -- New York (State). H paper. Withdraw the wire a couple of minutes after the candle goes out. Note the cloudy appearance of the film of water on the wire. The cloudiness was caused by the carbon dioxid formed while the candle was burning. Omitting the candle, hang the freshly wetted \yire in the empty chimney. Let the film of lime water remain within the chimney for the same length of time as when the candle was used. It does not become cloudy now. The cloudiness in clear l
. Annual report of the Agricultural Experiment Station. Cornell University. Agricultural Experiment Station; Agriculture -- New York (State). H paper. Withdraw the wire a couple of minutes after the candle goes out. Note the cloudy appearance of the film of water on the wire. The cloudiness was caused by the carbon dioxid formed while the candle was burning. Omitting the candle, hang the freshly wetted \yire in the empty chimney. Let the film of lime water remain within the chimney for the same length of time as when the candle was used. It does not become cloudy now. The cloudiness in clear lime water is a test or indication that carbon dioxid is present. Ques. What caused the white scum on the lime water which stood over night ? Alls. Some CO^ in the air. Qties. How does the CO2 get into the air ? Ans. It is formed whene\'er wood, coal, oil or gas is burned. The amount of COain ordinary air is very small, being only three parts in ten thousand. If the lime water in the loop be left long enough in the air it will become cloudy. The reason it clouds so quickly when the candle is being burned is that a large amount of CO2 is formed. Besides being made by real flames, CO2 is formed every time we breathe out air. Renew the film of water in the loop and breathe against it gently for two or three minutes. The presence of CO2 in the breath may be shown better by pouring off some of the clear lime water into a clean glass and blowing into it through a straw. An interesting question to end the lesson with is : \\1iy does water put out a fire ? The answer is, not alone because it wets, but because it cools the carbon, which must be hot in order to unite with the oxygen, and prevents the oxygen of the air from getting as near the carbon as 18. The test ivith the fiini of lime 7vater,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not per
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