From Table 10 it should be noted that the intensity of luminescence of pyrogallol oxidized with most oxidizers is actually less at the boiling point, a fact which I have repeatedly verified. Let us now see how these facts are to be explained. If we assume that luminescence is dependent on reaction velocity, the intensity of luminescence should increase with increasing temperature. Up to a certain limit this is what we find, but at temperatures above this limit the intensity of luminescence actually decreases. The duration of luminescence also decreases. There is an optimum temperature for luminescence in many cases and we can only conclude that luminescence depends not on a very rapid reaction velocity but on a certain definite reaction velocity. Assuming that this is true, how can we account for the anomalous fact that in high concentrations of oxygen, phosphorus will not luminesce or that in high concentrations of pyrogallol, there is no luminescence in presence of ozone or of oxidizer and H_{2}O_{2}. Of course with high active mass of oxygen (in case of phosphorous luminescence) or of pyrogallol (in case of pyrogallol luminescence) the reaction velocity must be greater than the optimum. If that is the case, then lowering the temperature should reduce the reaction velocity to the optimum and light should appear. However, as we have seen, not lowering but raising the temperature causes luminescence with high oxygen concentration or high pyrogallol concentration. TABLE 11 _Temperature, Concentration of Pyrogallol, and Light Production. An Equal Amount of M/20 K_{4}Fe(CN)_{6} is Mixed with Pyrogallol + 3 per Cent H_{2}O_{2}_ A = Concentration of pyrogallol (after mixing) ========================================================================= | Temperatures A +---------+---------+-------+--------+--------+--------+--------- | 0-2° | 10° | 20° | 30° | 50° | 75° | 98-100° --------+---------+---------+-------+--------+--------+--------+--------- M/4 | Negative| Negative| Good | Very | Faint | Fair | Faint | | | | faint| | | M/40 | Negative| Faint | Faint | Faint | Good | Bright | Good | | | | | | | M/400 | Faint | Fair | Good | Good | Good | Bright | Bright | | | | | | | flash M/4,000 | Bright | Bright | Bright| Bright | Bright | Fair | Negative | | | | | flash| flash| --------+---------+---------+-------+--------+--------+--------+--------- TABLE 12 _Temperature, Concentration of Ferrocyanide and Light Production. An Equal Amount of K_{4}Fe(CN)_{6} is Mixed with M/100 Pyrogallol + 3 Per Cent H_{2}O_{2}_ A = Concentration of K_{4}Fe(CN)_{6} exposed to light (after mixing)