656 



Mr. J. S. G. Thomas 



tiu 



to various rates ol air-flow, are shown in fig. 5. The 

 calibration curves shown in fig. 4, in the region of low 



'O 2 4 6 8 10 12 14 16 18 20 22, 24 26 28 30 32 34 36 38 40 42 44 46 48 5>0 



Velocities (cms per sec.voIumes reduced to o°c & 76omm) 



Variation in resistance of Second Wire for various Values of Heating Current. 



velocities, are markedly different from the type of cali- 

 bration curve afforded by the Morris type o£ anemometer. 

 Attention has been drawn to one feature of the calibration 



