[§ 123. Nickelin. —]

This is only German silver with a little less zinc, a little more nickel, and traces of cobalt and manganese. It behaves like German silver, but is an improvement on the latter in that all the faults of German silver appear upon a reduced scale in nickelin.

[§ 124. Patent Nickel. —]

Practically a copper nickel alloy, used to some extent by Siemens and Halske. It stands pretty well in the same relation to nickelin as the latter does to German silver. After annealing as for manganin it can be made into serviceable standards which do not change more than a few thousandths per cent. I have not come across a statement of its thermo-voltage against copper.

[§ 125. Constantin. —]

Another nickel copper alloy containing 50 per cent of each constituent. It appears to be a serviceable substance, having a temperature coefficient of 0.003 per cent per degree only, but an exceedingly high thermo-voltage, viz. 40 micro-volts per degree against copper.

1

German Silver.

2 __________ 3

Nickelin made byObermaier

4

Rheo-tane.

5 ___________6

PatentNickel

7. Manga-neseCopper.

8. Nickel Manga-neseCopper.

Dia-meter 1.0mm

Dia-meter 0.1mm

Dia-meter 0.6mm

Dia-meter 1.0mm

Copper

60.16

61.63

54.57

53.28

74.41

74.71

70

73

Zinc

25.37

19.67

20.44

16.89

0.23

0.52

...

...

Tin

...

...

...

...

trace

...

...

Nickel

14.03

18.46

24.48

25.31

25.10

24.14

...

3

Iron

0.30

0.24

0.64

4.46

0.42

0.70

...

...

Cobalt

trace

0.19

...

...

trace

trace

...

...

Mang-anese

trace

0.18

0.27

0.37

0.13

0.17

30

24

99.86

100.37

100.40

100.31

100.24

100.24

...

...

Specific resist-ance

30.0

33.2

44.8

52.5

34.2

32.8

100.6

47.7

Temp-erature co-efficient

0.00036

0.00030

0.00033

0.00041

0.00019

0.00021

0.00004

0.00003

The specific resistance is in "microhms, i.e. 10-6 ohms per cubic centimetre, and the temperature coefficient in degrees centigrade.

[126. Nickel Manganese Copper. —]

I can find no other reference with regard to this alloy mentioned by Lindeck. Nicholls, however (Silliman's Journal [3], 39, 171, 1890), gives some particulars of alloys of copper and ferromanganese. The following table is taken from Wiedemann's Beiblatter (abstract of Nicholl's paper, 1890, p. 811). All these alloys appear to require annealing at a red heat before their resistances are anything like constant.