220 Description of a Magnetic Electrical Machine. 
To make platina wire red hot. 
Fig. 6, shows the arrangement for this purpose, A being placed 
in contact with P and H. Whilst the platina wire is red hot, ether 
may be inflamed, gunpowder exploded, and other experiments of a 
similar nature be performed. 
WW e 
To render soft iron magnetic. 
Fig. 7. A, a piece of iron bent as in the figure. B, a soft iron 
keeper, which adheres to the iron on the connexion being made as 
_ represented, so Jong as the machine is in action. 
To obtain sparks of various colors by the use of different metals. 
Fig.8. Remove the break, and sub- 
stitute the brass piece B. Into the small 
hole insert a piece of wire C, of any 
metal, for instance gold. Let the ex- 
tremity of the spring Q be also of gold. 
On rotating the machine, sparks of a 
purple color will be obtained. 
To exemplify the disadvantages attending the mercury flood. 
Fig. 9. Remove the break, and fix the double blades B, in its 
place. Adjust the brass cup A so that the point will leave the sut- 
face of the mercury when the armature is vertical. ‘The brilliancy 
of the spark, as thus obtained, appears much greater that it is in Te- 
ality, the additional brightness being occasioned by reflection from 
the surface of the mercury. It is almost unnecessary to point out 
