Architecture and Design Treatment: Hugh Casson and James Gardner, o.b.e.
This Tower has been one of the landmarks of London since it was built in 1826. It remains, the only old building on the site, to serve as a beacon for the Festival. It is a beacon in two senses: it is a modern lighthouse with a double flashing beam welcoming visitors as far as 45 miles away when the weather is clear; it is a radio beacon directing radio signals to the moon and beyond it into outer space.
Originally the tower was built for making shot from lead. The molten metal dropping from the melting chamber at the top, formed perfect spheres as it cooled in its fall down the 120 feet within the tower. Those days are over now, but the tower still has a warm place in the heart of Londoners.
The lighthouse mounted at the top will flash from sunset to Exhibition closing time. It has a power of 3 million candles. It is of the most modern all-electric design and so takes up far less space than the older types which needed weighty lenses to intensify the beam. The light itself comes from a lamp of three thousand watts; an automatic device ensures that a second lamp can swing immediately into position should it fail. This lighthouse optic is the work of Chance Brothers, Ltd., who made all the glass for the original Crystal Palace a hundred years ago.
The radio beacon is above the lighthouse optic. The most obvious part of it is a large reflector which beams the signal from the aerial within it on to the moon. This is part of the radio telescope and is connected with the display in the Dome of Discovery by underground cable. In the Dome visitors can transmit signals to the moon and actually see them reflected back to the earth after about two and a half seconds.
The aerial of the equipment is placed on the top of the Shot Tower so that static interference from other electrical equipment nearby shall be at a minimum. The transmitter itself is unique in that it can operate whenever the moon is above the horizon. Earlier models can only be used at moonrise and moonset.
Visitors are able to see inside the Shot Tower. The entrance brings them onto a circular gallery. Above them, the original spiral staircase winds upwards to the top of the tower. Below, a kaleidoscope shows the varied character of the London scene in a changing pattern of pictures.
A short bridge leads from the Shot Tower to the brightly lit Tank Chamber where there is a small exhibit showing the development of the South Bank site.