THE VISCOSITY OF WATER. 53 
In the case of Tube II. the formula breaks down suddenly 
at a pressure between 35°7 cm. and 36°9 cm., the time of 
flow being about 24 secs., and the correction at pressure 
35°7 cm. more than 55 per cent. of the viscosity. The 
velocity in this case is 370 cm. per sec. 
For Tube III. the figures are, pressure between 20°4 cm, 
and 30°4 cm., time of flow less than 26 secs., second term 
60 per cent. of the viscosity; and for Tube IV. when the 
pressure is 27 cm. and the second term is nearly 60 per cent. 
of the viscosity, the deduced value is satisfactory, but an 
increase of pressure of 1 cm. brings about some decided 
change. The highest velocities reached in both cases, 
before the change, was about 340 cms. per sec. The curves 
Viscosity values (x 10°) at 50° C. collected, 
Pressure. | Tube I. | Tube II. | Tube III.| Tube IV. | Average. 
73 cm. 553 550 551 549 551 
EEO; 553 549 552 547 550 
147-7, 551 548 552 045 549 
20. 5, 550 549 554 546 — 5650 
DA ss a hat ca, 554 554. 
Onin Ys, on, aie a 546 549 
26 i vee a oe 551 551 
7 ae 550 en Re 549 550 
29 * 551 nye ae (588) 551 
BO 550 553 | (557) | (593) | 551 
31 45 547 ues deste (598) 547 
Sous, 4 549 beard Aes ae 549 
34 5 551 or ae (668) 551 
519 eae 554 of (562) ae 554 
36 a ae Ay (574) (709) 
sh | GBR) ie (571) ie 
DOr ig ats ate (578) (751) 
39 3 (573) uae (599) tee 
40 ,, | (591) | (559) | (612) | (814) 
ieee Re (65) di i 
43°, us om (837) 
oereees | 
Av. =| 00551 | -00550 | 00552 | -00548 | 
Mean Value = :0055@ 
