454 RIESS ON THE INCANDESCENCE OF 
Exp. 26.— 
Number Quantity of 
of jars. electricity. 
4* 9 The wire is just incandescent. 
10 one is red-hot. 
11 on is at an intense white heat. 
12 me is broken in the middle. 
Another wire of the same dimensions. 
Number Quantity of 
of jars. electricity. 
4* 12 The wire is intensely white-hot. 
124 <A piece of wire }” long remains fixed 
to the inner clamp (that which is 
connected with the interior of the 
battery). The remaining portion is 
broken into three pieces. 
Exp. 27.—A platina wire, 16 lines long and 0:0261 in radius, 
gave the following phenomena :— 
Number Quantity of 
of jars. electricity. 
4 12 The wire is incandescent. 
14 . 1s intensely incandescent. 
15 . 18 white-hot. 
16 .. 1s broken into three hooked 
pieces. 
Similar experiments gave like results. Platina wires were 
made incandescent by the discharge of a certain quantity of 
electricity through them, and were then, by an increased quan- 
tity, while hot, forcibly torn from their fastenings. This breakage 
occurs oftener near to the fastenings than at a distance; the re- 
maining portions of wire which project from the clamps are ge- 
nerally short, and sometimes there are none at all, The aspect 
of the ends of the broken wires shows that what takes place is 
simple breakage and not fusion, in confirmation of which fur- 
ther proof will be given below. 
I will here incidentally correct some erroneous statements of 
former observers. When the intense incandescence produced 
by discharge in a wire is observed, it appears as if the violent heat 
commenced at one end of the wire and proceeded thence to the 
other end. Cavallo * asserts that this begins always at the posi- 
tive end of the wire (that connected with the positively charged 
* Treatise of Electricity, London, 1795, vol. i. p. 311. 
