512 



Mr. J. S. G. Thomas on 

 Table I. 



Current in 

 Bridge. 



-r, . Resistance of unprotected wire. 



Ratio :— ■ " 



Resistance ot protected wire. 



Voltmeter not inserted 

 across covered wire. 



Voltmeter across 

 covered wire. 



002 



0-983 



0-2 



0-983 



03 



0-988 



04 



0-992 



0-5 



0-997 



0-6 



1000 



07 



1-002 



0-8 



1-004 



0-9 



1 007 



1-0 



1-012 



1-1 



1019 



1-2 



1-028 



1-3 



1038 



1-4 



1-048 



1-5 



1-057 



0-983 

 0-985 

 0-990 

 0-995 

 1-000 

 1-004 



1010 



1-020 



1040 



1-061 

 1070 



constant wLen tbe intensity of the air-current passing over 

 the sheath was varied, the bridge-current being maintained 

 constant. The method of calibration is best illustrated by 

 the consideration of the reduction of a set of observations as 

 recorded in the laboratory record : — 



Page 48. Anemometer No. 2 (a). 



Length of wires. — Protected 2'0140 cm.l f 910 p 

 Unprotected 2*0066 cm. J at - 1 U 



Mean diameter of unprotected and protected wire 0*00784 cm. 



Temperature coefficient of unprotected wire = 0*00291. 



R 17 ,3 = (>282 ohm, when c = 0*01 amp. 



Mean diameter of tube 2*0534 cm. 



Current 1*3 amp. 



Dry air flowing in tube. 



Ratio arm 1000 ohms. 



