jaggar: thermal gradient at kilauea 



401 



TABLE 1— Continued 



1917 

 January 26 



March 28 



LOCATION 



3.6 meters 

 above lava in 

 blowing cone 



cm. within 

 crevice 5 cm. 

 across. Bench 

 magma 



EX- 

 POSURE 



TEMPERATURE (SE- 

 GER CONE EFFECT) 



1130° fused 



1250° estimat- 

 ed interior 

 cone 



1350° estimat- 

 ed flame 



920° fused 



CONDITIONS 





2.5-cm. pipe, inserted in' ori- 

 fice 25 cm. diameter for a 

 length of 70 cm. Blast 

 flame emerging from ori- 

 fice, pipe bathed in burn- 

 ing gas within. Pipe fuses 

 and oxidizes to dripping in- 

 candescent product, eaten 

 through for length of 23 

 cm. at flaming window. 

 Color of pipe bright orange 

 inside cone, yellow oppo- 

 site flame. Temperatures 

 estimated from relative 

 glows and effects on steels. 

 (Pipe, cap, spring steel 

 container for Seger cones) 



Calibration test in glowing 

 orifice of cone, cherry-red 

 chamber. Seger cones in- 

 serted successively one at 

 a time on open wire. Basis 

 for weighting other tests 

 according to glow 



tively the actual and the corrected readings of the lower gradient 

 obtained in this manner, with the correction checked by meas- 

 urements of group 2, in which small pipes were used inserted to 

 a depth of 6 meters. 



The upper lake gradient (crosses) of April 5-6 shows three 

 points on a nearly straight line for 1, 2, and 6 meters of depth 

 with 30°C. increment of temperature per meter downward. 

 The average increment per meter of the lower, May 2, gradient 

 (dots) is the same, a line joining the 5-meter point and the 13- 

 meter point lying parallel to the April 5-6 line. The divergence 

 of the two above the 6-meter point may be due to instrumental 

 errors or may be due to a difference in convectional circulation 

 on the two days. On April 5-6 the southeast pool where the 

 experiments were made was streaming rapidly eastward on the 



