economy, and, for the many heavy taxes required from
them by the necessities of the State have surely an abundant
reason to be economical. I say it is impossible that so
sensible a people, under such circumstances, should have lived
so long by the smoky, unwholesome and enormously expensive
light of candles, if they had really known that they might have
had as much pure light of the sun for nothing.

Franklin's amusing letter had a serious aim, for in 1784 family expenses
were much augmented and adequate lighting by means of candles was very
costly in those days. However, conditions have changed enormously in the
past hundred and thirty-five years. A great proportion of the population
lives in the darker cities. The wheels of progress must be kept going
continuously in order to curb the cost of living, which is constantly
mounting higher owing to the addition of conveniences and luxuries.
Furthermore, the cost of light has so diminished that it is not only a
minor factor at present but in many cases is actually paying dividends
in commerce and industry. It is paying dividends of another kind in the
social and educational aspects of the home, library, church, and art
museum. Daylight saving has much to commend it, but the cost of daylight
and the value of artificial light are important considerations.

The cost of fuels for lighting purposes cannot be thoroughly compared
throughout a span of years without regard to the fluctuating purchasing
power of money, which would be too involved for consideration here.
However, it is interesting to make a brief survey throughout the past
century. From 1800 until 1845 whale-oil sold for about $.80 per gallon,
but after this period it increased in value, owing apparently to its
growing scarcity, until it reached a price of $1.75 per gallon in 1855.
Fortunately, petroleum was discovered about this time, so that the
oil-lamp did not become a luxury. From 1800 to 1850 tallow-candles sold
at approximately 20 cents a pound. There being six candles to the pound,
and inasmuch as each candle burned about seven hours, the light from a
candle cost about 1/2 cent per hour. From 1850 to 1875 tallow-candles
sold at an average price of approximately 25 cents a pound. It may be
interesting to know that a large match emits about as much light as a
burning candle and a so-called safety match about one third as much.

A candle-hour is the total amount of light emitted b