188 Parr .— The Response of Pilobolus to Light . 
Table IV gives the scale readings for the spectral regions of the Nernst 
lamp with the values expressed in ergs. The first determinations were made, 
using the energy value of wave-length +667 equal to 1*097 ergs, found 
in Table III, as the standard of comparison. The energy value of wave¬ 
length ±540 equal to 0*344 ergs, as found in this determination, was then 
taken as the standard for following spectral regions. Another series of 
measurements is then recorded where the Hefner lamp at 2 metres serves 
as the direct standard. The results from the data here given are later 
summarized in Table IX. 
Table IV. 
Light 
Standard of 
Spectral 
Galvanometer deflexions 
Average 
deflexion 
in mm. 
Ergs per 
sec. per 
cm . 2 
source. 
comparison. 
region. 
in mm. 
Nernst 
+ 667 (from 
+ 667 
445 — 1 55 = 290 
lamp 
Table ill) 
(Red) 
470-195 = 275 
470—210 = 260 
495-235 * 2 6o 
271 
1*097 
±612 
445-345 = i°o 
(Orange) 
440 — 360 = 80 
485-400= 85 
4 6 5-375 = . 90 
85 
o *344 
± 54 ° 
352 - 315 = 37 
(Green) 
373 - 338 ,= 35 
403-369= 34 
453 — 4 0 9 = 44 
37 
0.149 
99 
± 49 6 
497-475 = 22 
(Blue) 
523-500= 23 
540—520 = 20 
554-524 = 30 
24 
0*097 
99 
±470 
(Blue) 
448-430- 18 
468-445= 23 
490-475 = 15 
540-522 = 18 _ 
1 9 
0*077 
Galvanometer sensitivity 
changed. 
+ 540 used as standard. 
± 54 ° 
± 54 ° 
290-235= 55 
(Green) 
300-250= 50 
335-295 = 40 
345-305 = 4 ° 
46 
0*149 
>5 
±585 
410—320 = 90 
(Y ellow) 
410-315= 95 
415-320= 95 
420-335 = 85 
9 i 
0*295 
±540 
± 4 I 4 
355-340 = 15 
(Green) 
(Violet) 
330-318= 12 
340-325= 15 
336-327= 9 
12 
0*038 
Galvanometer changed in 
sensitivity. 
Hefner 
Angstrom 
T otal 
595-255 = 340 
lamp 
value 
radiation 
520- 180 = 340 
at 2 m. 
530-190 = 34 ° 
530-190 = 340 
340 
2*075 
Nernst 
Hefner 
+ 708 
545-260 jt 285 
lamp 
value 
(Red) 
520 — 260 = 260 
505 — 240 = 265 
1-616 
500-250 = 250 
265 
