SKY-WRITING

Rotorua Morning Post, Volume 1, Issue 123, 16 January 1932, Page 2

SKY-WRITING

LUMINOUS ADYERTISEMENTS THROWN ON THE CLOUDS. LONDON, Saturday. London'ers will shortly se6 night sky-writing visible for at least s.even miles; fbilowixig the inveiiti'on of the , gril • searchlight. Luminous advertisements thrown on ,the. clouds dufing expefiment^ at ^Hehdon and Portsmouth haye been read .at a- distanee of even 15 miles. - Thi's sky-writing project'or is the first in -the world that enables images to be thrown on the clouds as a whole, :br Jetter by letter, like a giant pencil wrifihg in space. ; The secret, as With the grid sfearchlight, lies ih the breaking Up of a ,mass of light into 300 separate rays by; iheahs of mirrors deflectihg eabh ray along a path to build up aii ultimate light image. - The largest messages so far possible are of . 24 letters, but there is nb reason why a bigger reflector, or tw,o projectors in conjunction, should not be used tcr east a longfer aiid deeper notice. A "^olunie of light totalling 3000 million carid^e-power causes an image of great intensity to be thrown on the clouds, makirig the Writihg sharp and clear even- when seen from brightly lighted streets;