[N110117], Technical Note, Francis Robbins Upton, September 25th, 1880

Item

Abstract

Fr 692 begins some TAE figures cost figures for 12 & 16 cp lamps, 50 cents per hp (not interesting). 695 Upton summary: "At present lamps are made which will give 16 candles for 1/8 of a horsepower of energy....." heat conversions, "The life of thse lamps will average 600 hours..." [Fr 697] "At 8 per horsepower of 16 candles the light is estimated as costing the company 1/4 ct per hour" or $1.50 for 600 hours, plus $.35 for cost of lamp = $1.85; figures $26,500 profit from sale & operation of 10,000 lamps. Comparison with costs at 9, 10, 11 HP. Fr 700 "tests show that 10 lamps of 12 candles each may be obtained from each horse power...." Use as their standard equivalent of 12 candles of gas because "it is found by experience that the devices by which the light may be made so much more practically effective add so much to the apparent light that every [one] is satisfied when told that it is giving a good gas jet. Also that gas cannot be burnt in practice so as to give out the maximum of light shown by the photometer...." TAE (fr 703) "12 candles photometer value will give at least 16 to 18 candles of effective light as compared with gas."

Mentions

Date

1880-09-25

Decade

1880-1889

Identifier

N110117

Folder Set

N110

Title

[N110117], Technical Note, Francis Robbins Upton, September 25th, 1880

Microfilm ID

36:695

Publisher

Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University

Timestamp

September 25, 1880