CHLORINE, BEOMINE, IODINE, AND FLUORINE. 165 



220. Chlorine a Disinfectant. Chlorine not only decom- 

 poses colors, but also, and probably for the same reason, the 

 volatile compounds which are formed in decay, and which 

 are so disagreeable to the smell and injurious to the health. 

 It may be used, therefore, for purifying all morbid matters 

 and infected atmospheres, and even for arresting decay. 

 Musty casks may be cleansed by washing them first with 

 chlorine water, and then with milk of lime. Mouldy cellars, 

 in which milk readily turns sour, can be purified by fumi- 

 gating them with chlorine gas, or washing them with chlo- 

 rine water or a solution of chloride of lime. 



221. Combustion in Chlorine. It was formerly supposed 

 that oxygen is the sole supporter of combustion, but we 

 have an example to the contrary in chlorine. You 



have already seen in 214 that certain metals 

 spontaneously burn in this gas. In the burning of 

 ordinary substances in chlorine the flame comes 

 from the union of chlorine and hydrogen, no union 

 with the carbon, so commonly attending combus- 

 tion, taking place in this case. Thus, if a candle 

 be let down into a jar of this gas, Fig. 68, it burns 

 as it enters with a dull red flame, but a dense cloud of 

 smoke arises, and the light is soon extinguished. The ex- 

 planation is this : The hydrogen of the tallow unites with 

 the chlorine, giving aflame; and the carbon, being separated 

 from the hydrogen, flies off in minute particles, and soon ex- 

 tinguishes the flame. The results of the combustion are 

 hydrochloric acid and lamp-black, the former com- 

 ing from the union of the hydrogen of the candle 

 and the chlorine, and the latter from the carbon 

 of the caudle, which can find nothing in the jar 

 to unite with, and so takes this form, some of it 

 being deposited in a dark film upon the sides of 

 the jar. If you moisten a slip of paper with oil Fig. ca. 



