266 
MEASUREMENT OF HIGH TEMPERATURES. 
Table 85. — Viscosity of air. Miscellaneous tests — Continned. 
[BULL. 54. 
p 
t" 
To 
9" 
rj" 
F(9") 
II. — Two thermo-couples touching the inner face of the naked helix. 
125. 30 
76.95 
165 
51.38 
6 
0. 0002514 
125. 29 
76.95 
165 
51.38 
6 
2513 
125. 29 
76.95 
76.95 
165 
165 
51.35 
51.45 
6 
6 
2514 
2511 
125. 31 
125.40 
76.95 
165 
51.68 
6 
2506 
124. 97 
76.89 
1780 
52.74 
964 
0. 0006947 
124. 95 
76.84 
1740 
51.69 
962 
6942 
124. 89 
76.80 
1770 
52.47 
959 
6966 
124. 85 
76.76 
1740 
52.05 
956 
6917 
124. 75 
76.66 
2520 
51.30 
1224 
0. 0008453 
124. 78 
76.62 
2580 
51.31 
1227 
8594 
124. 92 
76.59 
2700 
51.51 
1231 
9028 
2.811 
2. 809 
2.819 
2.789 
3.420 
3.477 
3.653 
III. — Temperature measured inside and (by contact) outside. 
124. 71 
76.61 
2940 
51.50 
C 1380 
> 1233 
1 0. 0009340 
124. 67 
76.58 
1800 
51.38 
C 1132 
\ 988 
1 0. 0006677 
124. 70 
76.60 
1800 
51.07 
C 1035 
\ 974 
1 0. 0007021 
3.778 
2.702 
2.841 
In the first part of Table 85 the couple is inserted into the helix, with 
its junction near the base, so as to be played upon directly by the flame 
of the burner. The temperatures so obtained fluctuate in value over 
so large an interval that it is difficult to get a fair mean value. This 
appears from the wide distribution of the points obtained on the curve. 
Their mean position, however, is unmistakably below (l-\-a6")*, a 
result consistent with the results of the foregoing tables, inasmuch as> 
the error of F(6") is here positive, because the error of 6" is positive. 
The helix in these experiments was naked. 
In the second part of Table 85 two thermocouples are inserted 
touching the inner face of the helix, with their junction at points re- 
spectively nearest to and farthest from the walls of the trough. The* 
results indicate a series of points at 960°, which are nearer the curves^ 
than before, whereas the results at 1,230° are abnormally high. Com- 
paring the temperatures at the two points of the internal face, I found I 
0i"= 1,255° and # 2 "=1,235°, so that even at the temperatures of the 
blast-lamp the differences of temperature for points on the inner face 
of the helix are not of serious magnitude. The discrepancy mnst 
therefore be looked for in thermal differences between the inside and! 
outside faces of the helix. 
In the third part of Table 85 measurements of the kind just specified 
are given. The two figures under 6" are thermal data for the inside 
(920) 
