We may compare this subject to a beautiful house the inside of which you would like to examine from top to bottom. We have opened the door for you; now walk in and examine everything. There may be a great many stairs to climb, but what you see and learn will repay for all the trouble.
[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.
-Plain print and punctuation errors fixed.
End of Project Gutenberg's ABC of Electricity, by William Henry Meadowcroft