Page 6 Advertisements Column 2

Otago Daily Times, Issue 18514, 27 March 1922, Page 6

- One of I lie greatest difficulties encountered when erecting a big telescope is ihe problem of making its huge, tube sufficiently rigid. Professor Todd lias conceived a new way of tackling the problem; he proposes to use Ihe shaft of a mint’ ns l.lie tnlio of the greatest telescope ever made. In 1924 the mysterious planet Mills will be nearer lo ns than it lies’ In en for a, century. Here, if only i\e can si"’/, it. is oils bust chance of discovering whether people like ourse-hes live upon its surface. Professor Todd's "mm'' lelesroj'i " is In bn more than a quarter id a Hide, in length, and hOft ill diameter. It "ill bring Mars within one mile and a-liall ot die observer’s eye. Toe magnifying mirrors used in great telescopes are difficult to make and very costly. What a 30ft min or would cost no one can s<i\ it i,Oglu easily run into a quarter of a million pound-- and take 10 to Ifi years to make. Professor Todd is not going to bate a glass mirror at all. Me proposes to have al the foot of his telescope a great bowl filled with quicksilver. The bowl will be rotated by means of it motor, and as: it spins the mercury will assume the ncecssary concave shape. Once the proper speed has Iwf.ii found by experiment, a mirror will be obtained capable of magnifying 25 million limes. With such a telescope you could read the lettering on a penny 400 miles t.wuy 1