[1] The filaments in modern "Mazda" lamps, as made at the Edison Lamp Works, are strips of metallic tungsten.

[2] The batteries we will now describe are for closed-circuit work only, and they are never used for open-circuit work. But there is a type of battery made that is available for either open or closed circuit operation. This is the Edison Primary Battery, which will be described later on.

[3] Practically, there is always one more negative plate than positive plates in a regular storage-battery cell. Consequently, a standard cell always contains an odd number of plates.