Project Gutenberg #4710
The Story of Electricity
John Munro
1902Munro's popular history of electrical science and its early applications, prepared chapter by chapter from Project Gutenberg HTML.
Project Gutenberg #4710 Public domain in the United States Cover source Local typographic cover created for MojiMori from public-domain source metadata
Section 20 of 20
LIGHT UNITS
3
words at B2 or above
A1
A2
B1
B2
C1
C2
C2+
highlighted
at or above your level
The British Unit is the light of a spermaceti candle 7/8-inch in diameter, burning 120 grains per hour (six candles to the pound). They sometimes vary as much as 10 per cent, from the standard. Mr. Vernon Harcourt's standard flame is equal to an average standard candle.
The French Unit is the light of a Carcel lamp, and is equivalent to 9 T/Z British units.