1337 
0.01412 
0.03925 
0.01414 
0.03925 
0.01411 
0.03925 
0.01411 
0.03925 
The following- tlu'ee experitiients were eavried out in an atmosphere 
of nitrogen. 
0.01416 
0.03928 
0.01412 
0.03924 
0.01411 
0.03926 
Diffused light 
190' 
0.0635 
( Darkness 
190' 
; Do 
1 Diffused light 
190' 
Do 
i Darkness 
190' 
Do 
1 Diffused light 
190' 
Do 
1 Darkness 
190' 
Do 
t Diffused light 
190' 
Do 
( Darkness 
190' 
Do 
( Diffused light 
190' 
1 0.0635 
( Darkness 
190' 
Do 
Diffused light 
190' 
Do 
2) 
( Darkness 
190' 
Do 
1 Diffused light 
190' 
Do 
3) 5 
f Darkness 
190' 
Do 
i following three 
experimenis 
were cai'ried ( 
•bon dioxide. 
( Diffused light 
190' 
0.0635 
* ) j 
( Darkness 
190' 
Do 
i Diffused light 
2) 
( Darkness 
190' 
Do 
190' 
Do 
( Diffused light 
3) 
1 Darkness 
190' 
Do 
190' 
Do 
0.01415 
0.03928 
0.01411 
0.03928 
0.01413 
0.03926 
Evidently the behavionr of this aetinonieter is quite regnlar. 
Potassium oxalate uiay be sebsiituted for ammonium oxalate and 
the potassium oxalate-iodine actinometer vvorks as well as the ammo- 
nium oxalate-iodine actinometer. 
Eder’s (Sifzungsber. der Kaiserlichen Akademie der Wissenschaften, 
Wien, October 1879) actinometer, whieh consists of a mixture of a 
saturated solution of ammonium oxalate and mercuric chloride, is 
generalij used ; but unfortnnately tliere are several disad van tages of 
this actinometer. Winther fZeit. Wiss. Photo (1909) I, 409) lias 
shown thai oxygen plays the part of a negative catalysor in the 
pholo-catalysis of the reaction of a solution of mercuric chloride tind 
ammonium oxalate in light. It is well-known that after exposure 
to sunlight Eder’s solution, begins to separate mercurous chloride 
according to the following eqnation : 
86 
Verslagen der Afdeeling Xatuurk. Dl. XXIY. AP. 1915/16. 
