37400 37380 37360 373.40 373.2O He 3730 0200400600800100O tp(torr) FIGURE 17-15 Temperature readings of a constant-volume gas thermometer for the boiling point of water at loo atm are plotted, for different gases, as a function of the gas pressure in the thermometer at the triple point (Ptp ote that the amount of gas in the thermometer is reduced so that tp O, all gases give the same reading, 373.15 K. For pressure less than o.lo atm (6 torr), the variati shown is less than O07 K