ARTIFICIAL DAYLIGHT.

Daily Telegraph (Napier), Issue 3121, 29 June 1881, Page 4

ARTIFICIAL DAYLIGHT.

(From the Scientific A merican )

The lighting of large interiors from without. —that is, by surrounding the space to be illuminated with powerful lamps, so placed as to fill the air with diffused light—is certainly a bold, though, not entirely a novel proposition ; yet, either to attract attention or to establish an important economic principle, the Northern Electric Light Company are 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 ti> 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 rislc of failure, and to furnish the means for making such a crucial test of " artificial daylight," on condition that the Government would agree to accept the innovation in case il 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 nob 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 point about the Capitol grounds, it was proposed to erect six iron towers, to be surmounted by circular conical lantere, lift in diametei , , 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 were 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 200,00-) average gas-burners. 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 less than three dozen largo 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 350,000d01. The estimated running expenses of the system, including repairs, is 60,000d0l a-yeav—the present means of illuminating the Capitol costing annually upwards of 110,000, the city paying 60,000d0l 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. Congress declined to have anything to do with it.