& 
Barus and Strouhal— Viscosity of Steel. 23 
3. Tables 31 and 82 contain our results with the tubular 
apparatus. , is the inner radius, g, the outer radius of the tube. 
Q and g denote the right sections of brass tube and steel wire 
respectively. Of course sections of metallic surface are meant. 
The inclosed wire is twisted alternately in opposite directions 
as is indicated by the sign of ¢. The result is similarly indi- 
cated by the sign of g. Subscripts s and 6 refer to steel and 
brass respectively. ‘Lable 31 contains results for a thick tube, 
table 32 for a thin tube. Hard or soft rods are inserted, as 
indicated. 
Table 34 is mentioned below. 
TABLE 31.—APPaRATUS (tubular) IT. 
2p,=0-188™, 
” 2.=0°320. 
hard, 20==0°127™; Q=0:-053°""; g=0-0127™"; Q/q<4'5. 
R=260™; [=22™. Rods: No. e, brass No. 89, steel, glass- 
Date. @x102 | hy | 0x 108 Date. @x103 | fo | box 108 
7/7, 9202™| 0-308] *0-:00) +0-002/|14/7, 8°57") 0-248) *0-00| +0-000 
1225 0-390) -3°22) —0-080 10 27 0-248} 1:50) +0-000 
5 18 0-420) 8-27| —0-110 12 45 0-248; 3°80) +0-000 
8/7, 9219™| 0-460} 24-28) —0-150 4 45 0-250] 7:80) +0-002 
12 48 0-465| 27-77; —0°155||15/7, 10> 46™ 0°250| 25°82) +0-002 
5 50 O42 76) 32:80) —O-T66) 15/7102 4emi) a, £500 ae 
Dit gh 30™ 0°500| 47-47) —0°190 WO) B36) 0°310 1°82} —0:°005 
Ot gh 50™ 0-456 +000 =—() 0106) ||hae 4 2% 0°306 5°68; —0:009 
12 12 0°337 Sean ee VG/T, 92 20™ 0°2991 22°57) —0:016 
5 20 0°283 8:50) +0711 HD: ; 
10/7, 8" 09" 9-299| -93°39| 0-178 ean hard steel rod, No. 39, again 
12 09 0°208} 27°32) +0°192 fh j 
5 18 0-191] 32:47] +0-209|/16/7, 95 25™ 0:948] *0:00] +0-032 
11/7, 9820™| 0-160] 48°50} +0-240 11 26 FO eel One 
11 35 | 0-151] 50-75] +0-249 FSU obecel Uae teouee 
my aie Ah 15™ 0-540 *0-00 +0°060 Ate gh 50™ up Oo8 23°42) —0'113 
7 00 0°630 2°75| —0:030 18/7, gh Q7m 1151} 47:03) —0:171 
Fie2,9, 0°743| 25:23) —0-143]|19/7, gh 4]m™ 1185) 72:27) —0:205 
c re ee aa : 5 15 1-186] 79-83] —0206 
ass-hard rod replaced by a soft steel||56 7, GiG 1-207 s 0-99" 
rod, viz: No. 40, annealed, 450°, 1, ZG aah au eee teal 
2p=0°12Te™, 20/7, 10 50 0-458] $0-00|, —0-062 
Les 0416 0-47; —0:020 
13/7, 105 04m 0°876| *0-00| +0:004 11 50 0°396 1:00} +0:000 
12 30 0°886 2°43; —v-°004 1 53 *0°354 3°05] +0°042 
5 05 9°890) 7:02; —0:°010 3 44 0°330 4:90) +0°'066 
14/7, 855m a 22°85| —0°014 6 35 0303) 1-75} +093 
21/7, 102 02™ 0°247| 23°20) +0:149 
| 12 18 | 0:239| 25-47| +0-157 
* Total twist ~,—(— 1,)=180°, twist of steel 7,, positive. 
+ Total twist --,+(—w,)=180°, twist of steel, positive. 
