As a teenager I used to read American superhero comics like DC and Marvel and I was always tempted to respond to the full page advertisements for such things as a complete two hundred piece civil war army for $1.49, a miniature secret camera for only $1.00 or a free Charles Atlas body building course.
What prevented me filling in the order form and sending off the cash was not the rather critical fact that I had no idea how to exchange my paper round money into dollars but rather the fact that I didn’t know what a ZIP code was. I concluded that it was some sort of secret code that prevented overseas orders from being processed and so never had the pleasure of sending off my order form for those intriguing items.
As it turned out there is nothing secret about it at all. The ZIP code is the system of postal codes used by the US Postal Service. The letters ZIP are an acronym for Zone Improvement Plan and were chosen to suggest that the mail travels more efficiently, and therefore more quickly, when people sending post use it.
By the early 1960s improvements were needed in the postal service due to increasing volumes and on 1st July 1963 ZIP codes were announced for the whole country. This might not sound like a really really big news item but I mention it because for many years I had a lot of difficulty understanding what a ZIP code was as post codes were not introduced to the whole of the United Kingdom until 1974 and then no one really used it for at least the next twenty years or so. (Post codes were introduced in Australia in 1967 and in Canada in 1971 although here Trade Union opposition held up full implementation until 1974).
Most of all I wanted a pair of X-ray specs, mostly because the advert seemed to suggest that whilst it might be fun to be able to see the bones in your hand, it would be a whole lot more fun to be able to see through clothing and there was always a curvy girl in the advert that suggested that this was a real possibility.
But, let’s think about it for a minute. This is how my science dictionary explains X-rays:
‘X-rays are a type of electromagnetic radiation with wavelengths of around 10-10 metres. When X-rays are being produced, a thin metallic sheet is placed between the emitter and the target, effectively filtering out the lower energy (soft) X-rays. This is often placed close to the window of the X-ray tube. The resultant X-ray is said to be hard. Soft X-rays overlap the range of extreme ultraviolet. The frequency of hard X-rays is higher than that of soft X-rays, and the wavelength is shorter. During an X-ray the electrons decelerate upon colliding with the target and if enough energy is contained within the electron it is able to knock out an electron from the inner shell of the metal atom and as a result electrons from higher energy levels then fill up the vacancy and X-ray photons are emitted.’
Well, that all sounds rather complicated to me, and X-ray machines costs many thousands of pounds so thinking back it seems highly unlikely that a pair of cardboard specs costing a mere $1.00 was going to be able to deliver the sort of advanced level of technical process that would enable me to see through girls’ clothing.
Actually the lenses consisted of two layers of cardboard with a small hole punched through both layers. A feather was embedded between the layers of each lens and the vanes of the feathers were so close together that light was diffracted, causing the user to receive two slightly offset images. Where the images overlapped, a darker image was obtained, supposedly giving the illusion that one is seeing an X-ray image of dark and light. I know now of course that this isn’t a real X-ray machine at all and I am retro spec tively glad that I never sent off my money and purchased a pair.