United Steel Company had been employed to manufacture the steel for the telescope, and I... there is... I had the instinct to dictate every day a day-to-day diary of the proceedings in that year and thereafter, and that diary still exists in my office at Jodrell Bank. It's a great thick book of typescript, if anybody's ever interested to review what happened in those years.

In 1953, the building began. The trouble was that no cranes existed of... sufficient to deal with the mass of steel and the height of steel, which were being involved. So Husband had arranged to build his own cranes on a series of gantries. He first built one big gantry, using an available crane of about 20 or 30 foot high. And on this he mounted that crane to build another crane on another gantry, until he got a crane on a huge, massive scaffolding, which could be rotated and... around the circumference of the telescope, and which would be capable of handling masses of steel to a height of 180 feet or thereabouts.

Now, of course that was a problem in those days. Today it would be no problem. Such cranes for commanding such heights and loads are very easy to obtain. It's just indicative, though, of the difficulties, the engineering difficulties, which were faced, of... which were entirely unforeseen in the original estimates for building this telescope. The work continued. The scaffolding was erected, and first of all, the great concrete block for the central pivot had also been supported on reinforced concrete to the Keuper Marl, and the central bearing was to carry a diametrical girder on which the outrigging bogies bearing the main structure could be rotated. But the only actual location of the telescope to the ground was by the central pivot. It was to move freely, on its bogies, on the 320 foot double railway track. The details, day by day details, of the construction are recorded in my book. It would be quite unnecessary to go into the details now, except in general that the steel work, I'd been taken to Scunthorpe, and where I actually saw the great masses of steel pouring out of the furnaces, which were then welded into the girders for the telescope.

By 1950... nothing much happened in 1953, until in 1954 the structure began to ascend, the diametrical girder had been constructed, and the two towers, now known as Green Tower and Red Tower, had moved to a height of 20 to 30 feet. It was at that time in late 1953 and 1954 that I wanted the design, I made a change in the design, and the reason for that change was a purely astronomical one. The telescope that was being built had an open mesh bowl of four inches.

Now, in... I think it was 1952, 1953, the... what was a remarkable discovery of a prediction made during the war by van de Hulst and Oort hiding in secret from the Germans, in Holland, they had worked out that there should be a high frequency spectral line from neutral hydrogen, and this might be detectable on the wavelength of 21 centimetres. Well, at about this time, the exact date, I'm... it was '52 or thereabouts, simultaneously in Holland, in Australia and in America, the work on the attempt to detect this important spectral line from neutral hydrogen had succeeded, and there was in fact a simultaneous publication in Nature from these three sources about the discovery of the neutral hydrogen line. Now, of course, this was recognised to be of immediate importance in the attempts to unravel the nature of the galaxy, and it was evident to me that a telescope with a diameter, with a mesh of four metres would be no good on this wavelength or frequency. You must recall that I was still primarily interested in long wavelengths, because of the cosmic ray air showers. And so I asked Husband to change the mesh, to first of all the smaller diameter and then to make the inside internal 100 foot diameter of the telescope, I think it's a mesh of an inch or two inches, so that at least the centre 100 foot could be used on a wavelength of 21 centimetres. This, of course, increased the windage, and led to the introduction of a considerable strengthening of the bowl support, and at that time the idea was to build the bowl by a series of girders moving out from a cylindrical axis moving between the two towers. That was all right. The redesign was made with this girder stretching between the tops of the two towers and both carrying, this single, massive girder carrying the structure of the bowl, and the deflections were then calculated to be quite compatible with the new accuracy on which I wanted the telescope to work.