Kilcullen Town Hall's Film Projector

Movie projector from Kilcullen Town Hall Cinema. © Eugene Brennan

I was examining the nameplate (rating plate) of Kilcullen Town Hall's former film projector the other day, now located in a corner of the porch of the heritage centre. The Peerless Magnarc carbon-arc lamphouse, paired-with the projector and  manufactured by the J. E. McAuley Manufacturing Company of Chicago, Illinois, ran on DC electricity. A rectifier may have been built into the projector to convert mains AC to DC, or possibly it was a separate piece of equipment.
Arc lamps were used as an intense white light source for projectors, essential for producing a bright image on the screen. They were also used of course in search lights during WWII, for spotting enemy aircraft. Arc lighting generates large amounts of harmful UV radiation and filters would presumably have been used in the optics to block this. Electric arcs also produce a lot of heat, as anyone who has ever done electric welding would know, and again, filtering would have been necessary to protect the film. Carbon rods were consumable items used in arc lamps, just like the rods used for arc welding and had to be replaced frequently. In the early days of movies, film stock was manufactured on a highly flammable nitrate base and fires were common. It's thought that a candle ignited a reel of nitrate film, resulting in the Drumcollogher tragedy of 1926, in which 46 people perished.

I'm not sure what the "motor" is, referred to in the spec. Since the lamp was an add-on unit to the projector, it was probably not the film feed motor, but rather a motor powering a cooling fan for the lamp or one that fed the electrodes as they were consumed.

The photo mounted on the projector shows actor Paul Newman standing in front of it on the occasion of his visit to Kilcullen over 20 years ago. At that stage, the projector was still located in the projection room.

In 2006, Brian Byrne published a more detailed article in the Kilcullen Diary which provided more information about the projector’s projection unit.

Arc volts 31 - 46
Arc amps 32 - 100
Motor volts 31 - 110
Motor amps 0.5 - 1.4

J.E. McAuley Mfg. Co.
Chicago, ILL 
United States of America

Rating plate attached to the projector. © Eugene Brennan

Rainbows Don't Have Seven Colours

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"Richard of York Gave Battle in Vain" or ROYGBIV was the mnemonic we used in school to remember the seven colours of the rainbow: Red, orange, yellow, green, blue, indigo and violet. But did you know there aren't actually seven colours? Isaac Newton, the 17th century scientist decided to add another colour because "7" was a perfect and divine number (God made the world in seven days, there were seven known objects in the Solar System, seven musical notes on a scale etc). So he added the seventh colour, indigo, whereas there are actually only six. Rainbows are composed of a continuous variation of spectral wavelengths from short to long as white light is bent or refracted, and "smeared" or dispersed by differing angles depending on wavelength as it passes from air through a different medium such as glass or water. The apparent colours are in the eye of the beholder simply because we have cones for red, blue and green in our eyes. Mantis shrimps have many more than three types of cones in their eyes than us, and would see more than six colours in a rainbow.

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