Page:Incandescent electric lighting- A practical description of the Edison system.djvu/39



In Fig. 10 and Fig. 10a is shown an incandescent lamp, both in and out of its receptacle or socket. The lamp is formed of an elongated glass bulb, into the bottom of which passes a hollow glass stem; this stem is closed at its top and has imbedded in it small conducting wires of platinum which support a loop-like thread or filament of carbon or charcoal, made from the fibre of bamboo. The bottom of the tube is melted or sealed to the glass bulb so as to make the latter air tight at that point, and after the air contained in it is exhausted through a tube of glass attached to its top and connected with an air pump, that end is also hermetically sealed, by- melting the glass at that point into a tiny glass knob, as shown in the cut.

Attention is then given to the bottom of the lamp; about which is moulded a