---------------+--------------------------------- |Temperature, degrees, Fahrenheit. Contact Period.+-----------+----------+---------- | 36 | 70 | 98 ---------------+-----------+----------+---------- Nil | 424 | 424 | 424 5 minutes | 320 | 280 | 240 1.5 hours | 148 | 76 | 12 4.5 hours | 38 | 14 | 3 24 hours | 2 | 0 | 0 48 hours | 2 | 0 | 0 ---------------+-----------+----------+---------- [A] Results are _B. coli_ per 10 c.cms. TABLE IX.[B]--EFFECT OF TEMPERATURE AVAILABLE CHLORINE 0.2 PARTS PER MILLION ---------------+--------------------------------- |Temperature, degrees, Fahrenheit. Contact Period.+-----------+----------+---------- | 36 | 70 | 98 ---------------+-----------+----------+---------- Nil | 240 | 240 | 240 5 minutes | 240 | 250 | 235 1 hour | 245 | 235 | 195 4 hours | 215 | 190 | 170 24 hours | 143 | 130 | 115 48 hours | 130 | 59 | 19 72 hours | ... | 28 | ... 96 hours | ... | 16 | ... 120 hours | ... | 6 | ... ---------------+-----------+----------+---------- [B] Results are _B. coli_ per 10 c.cms. The reaction velocity of a germicide is proportional to the temperature[9] and the influence of temperature may be mathematically expressed by the formula _K__{1}/_K__{2} = _[theta]_(_T__{2} - _T__{1}), in which _K__{1} and _K__{2} are the constants of the reaction at temperatures _T__{2} and _T__{1}, respectively, and _[theta]_ is the temperature coefficient. From the value of _[theta]_, the velocity constant of a germicide for any temperature may be calculated from the equation _K__{_T_} = _K__{20}° × _[theta]_^{(_T_ - _T__{20}°)}. _K__{1} and _K__{2} are obtained from the formula _K__{_T_} = log(_N__{1}/_N__{2})/(_t__{2} - _t__{1}) in which _N__{1} - _N__{2} is the number of bacteria destroyed in the interval _t__{2} - _t__{1}. A reduction of temperature also lowers the oxidizing activity of the chlorine so that a greater concentration is available for germicidal action. This is shown by the results plotted in Diagram II. [Illustration: DIAGRAM II EFFECT OF TEMPERATURE ON ABSORPTION OF CHLORINE BY WATER