AT THE BOUNDARY OF A LIQUID IN MOTION. 
573 
Tvbe N'o. 1. —{r ~ '0803 cm. ; I = 30‘9 cms.). 
Average pressure. 
Temperature. 
Time of flow. 
Value of /<■ 
cms. 
o 
/ // 
16-825 
13-2 
2 46-0 
’01448 
15-320 
16-6 
3 3-3 
•01456 
The tube was then cleaned with dilute nitric acid, 
hut was only changed by 0‘08 per cent. 
The radius was re-determined, 
Average pressure. 
Temperature. 
Time of flow. 
Value of fi. 
cms. 
o 
/ // 
17-215 
14-0 
2 37-5 
•01406 
16-37 
14-6 
2 42-8 
•01382 
Cleaned with hydrochloric acid and potash. 
Average pressure. 
Temperature. 
Time of flow. 
Value of /(. 
cms. 
o 
/ // 
17-86 
18-7 
2 32-5 
•01412 
Another tube was then taken and polished inside by working it along a stretched 
string, covered with fine emery powder. 
Tube No. 2, polished with emery powder.—(r = '08094 cm, ; I — 23'30 cms.) 
Average pressure. 
Temperature. 
Time of flow. 
Value of //. 
cms. 
i // 
16-43 
13-0 
2 9-5 
•01510 
1469 
13-0 
2 23-6 
•01497 
The inside was then coated with a film of oil. I’he radius was re-determined, 
r = '08003 cm. 
Average pressure. 
Temperature. 
Time of flow. 
Value of /<. 
cms. 
o 
/ II 
16-56 
13'6 
2 13 
•01494 
1507 
13-6 
2 27 
•01502 
