ARTIFICIAL DAYLIGHT.

Globe, Volume XXIII, Issue 2242, 9 June 1881, Page 3

ARTIFICIAL DAYLIGHT.

[From the “ Bcientiflo American.”] The lighting of large interior* from without —that i*, by surrounding the *pace to bo illuminated, with powerful lamps, bo placed as to fill the air with di£fu*ed light—ia certainly a bold, though not entirely a noTol proposition; yet, either to attract attention or to establish an important economic principle, the Northern Electric Light Company is begging Congress to allow them to light in that way the capitol at Washington, At first they asked Congress to appropriate money enough to defray the actual cost of illuminating the capitol and the grounds about it to the brilliancy of broad day, thus making interior lamps unnecessary. But no disposition being shown by Congress to encourage the experiment, the friends of the project subsequently offered to assume the risk of failure, and to furnish the mentis for making such a crucial test of “ artificial daylight,” on condition that the Government would agree to accept the innovation in case it succeeded, and the saving in the cost of lighting the Capitol should prove in three years

equal to the cost of the system. This proposition appears to have met with no greater favor than the first, whether from suspicion as to its purpose or feasibility, or because the expiring Congress had larger and more pressing interests to consider, does not appear. The plan proposed contemplated a crown of electric lamps, 150 in number, surrounding the dome of the Capitol, and so arranged as to shine into the [skylights in the roofs of the wings of the building. In addition, at various points about the Capitol grounds, it was proposed to erect six iron towers, to be surmounted by circular conical lanterns, lift, in diameter, and from 125 ft. to 200 ft. above the ground, or 50ft. higher than the roofs of the wings of the Capitol. Each lantern was to contain fifty electric lamps. The 450 lamps upon the dome and in the tower lanterns wore designed to be about 6000 candle power each, aggregating something like forty times the light power now employed in and about the Capitol, or about that of 200,000 average gasburners. This light, it is estimated, would not only illuminate the interior of the building as well as daylight, but would furnish a surplus sufficient to remove the need of street lamps anywhere in the city. To generate the electric current there would have to be supplied not lees than three dozen large dynamo-electric machines, capable of absorbing the power of four steam engines of 300 horse-power each. The cost of the system was estimated at 350,000 dols, distributed as follows ; Dais. Four hundred and fifty 6000 caudle power electric lamps, at 80 dols ... 36,000 Thirty • six large dynamo - electric machines, at 3600 dols 129,600 Four 300 horse-power steam engines, ’ twelve boilers, and the requisite fixtures and shafting 40,000 Houses for boilers and machinery ... 25,000 Six iron towers —two 200 ft high, two 150 ft high, two 125 ft high, including lanterns, reflectors, elevators, and foundations 80,000 Setting up machinery and apparatus, including cost of subterranean wires ... .. ... ... 15,000 Land 15,000 Engineering and contingencies ... 9,400 Total 350,000 The estimated running expenses of the system, including r epairs, is 60,000d01. a year—the present means of illuminating the Capitol costing annually upwards o f H0.000d01., the city paying 60,000d01. more for street lamps. The aggregate illumination promised by the new system is twenty times that of all the outdoor lamps in Washington and all the lamps in the Capitol building combined ; or a light equivalent to bright moonlight throughout the city, and diffused daylight in and about the Capitol. [We learn that Congress does not seem particularly captivated by the above scheme, and declines to have anything to do with it.j