152 - MR JAMES DEWAR AND DR M‘KENDRICK ON THE 
light after it had passed through a solution of bichromate of potash (red 
light) :-— 


Observations. | pact, | Ontmpect | * eee | age | daapaees | ~ removal 
99 37 39 38 40 Rise of 2. | Rise of 2 
100 38 40 39 40 Rise of 2 Rise of 1 
101 35°5 37-2 35°5 36°5 Rise of 1°7 | Rise of 1 
102 32 33°5 31 31°4 Rise of 1°5 | Rise of °4 
103 36 38 34°5 35 Rise of 2. | Rise of 5 
At this stage the electro-motive force fell so as to permit readings to be made 
on the true galvanometer scale. 
104 340 360 350 355 and sudden fall | Rise of 20 | Rise of 5 
105 270 283 260 268 do. Rise of 13 | Rise of 8 
106 235 240 235 238 do. Rise of 5 | Rise of 3 
107 242 248 245 248 do. Rise of 6 | Rise of 3 
108 235 240 238 239 do. Rise of 5 | Rise of 1 
109 224 231 224 225 do. Rise of 7 | Rise of 1 
110 217 224 217 219 do. Rise of 7 | Rise of 2 
111 209 215 207 208°5 do. Rise of 6 | Rise of 1°5 



These experiments show a rise on the impact of light, a fall during the con- 
tinuance of light, and another rise, or inductive effect, on the withdrawal of 
light. 
SERIES III.—Eve or Froac. 
On placing the eye om the cushions, and opening the key, a deflection of 
nearly 500 degrees of the galvanometer scale was obtained. The readings were 
made on the attached scale just alluded to. The following observations were 
then made :— 
Obs. 112. A platinum spatula was heated to a red surface in the flame of a 
Bunsen burner at a distance of 24 feet. Before it reached a red heat the galvano- 
meter stood at 47. During the emission of red rays it slowly rose to 49. When 
spatula cooled, it fell to 48. 
Obs. 113 and 114. A little carbonate of soda was placed on the spatula, and 
introduced into an almost colourless Bunsen flame. Rose from 48 to 51, and on 
withdrawal sank to 48. This experiment was repeated. 
Obs. 115. A little nitrate of strontia was placed on spatula, and pushed into 
flame. Rose from 48 to 49°5. No inductive effect was observed. 
Obs. 116. Experiment with nitrate of strontia was repeated. Rose from 50 — 
to 53°5, and on removal sank to 50. 
Obs. 117. Again repeated. Rose from 50 to 53. On removal rose from 52 
to 54. 

