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the microphone (in rest) and a Leclanché-cell amounts to about 0.08 
Ampére. The curve of fig. 5 shows clearly that there is not the 
slightest question about the iron being saturated when the current 
has this intensity. 
I then considered whether the iron might not become slower in 
changing its magnetic condition if the magnetism reached a higher 
degree, even though there were no question about an approaching satur- 
ation. That in other words a piece of iron would need more time to 
change its magnetism from 20 to 18 or 22 than from 6 to 8 or 4. 
To investigate this the experiment shown in fig. 6 was made. 
T is a translator without iron core, consisting of 2 > 1500 
turns; thickness of wire 0.4 mM., resistance of each of the two 
series of turns about 21.5 Ohm. The battery consists of a 
number of secondary cells, of which I used respectively 1, 4,8 and 
11 cells in the four different sets of experiments I made with this 
apparatus. For the rest the sketch speaks for itself. If the Morse- 
key was not pressed down, a telephonic alternating current passed 
through the primary wire of 15 A; if on the contrary the key was 
pressed down, a constant current also passed through it. 
For the proportion between the strength of the current, induced 
in the secondary wire, if only an alternate current passed through 
the primary wire, to that of the induced current when also a 
constant current passed through the primary wire, I found: 
for the currents: 0.08 0.35 0.66 0.88 Ampère, 
the proportion : GAT OTE ker EO ee at E49, 
The number of readings and the calculation of the mean value were 
for these measurements quite similar to those given in Tables II 
and III. 
From the above it is evident that the constant currents 0.08, 
0.35 and 0.66 Ampère have no perceptible influence on the 
intensity of the induced current. Not until the strength of the 
current was 0.88, did this influence become perceptible: there the 
induced current becomes distinctly feebler when the constant current 
flows through the coil. But with that strength of current the magn- 
etism is no more proportional to the intensity of the current, as 
the curve of fig. 5 shows. The slowness of the iron cannot now 
be regarded as the cause of the induced current becoming feebler, 
but, with such a current, this can be explained from the saturation 
