Granite devices

Aldermaston had worked hard producing the Granite devices, which were now abandoned in favour of the American designs. Assimilating the American data took some time. The Mark 28 in the form of Red Snow would be used not only in the free fall bomb for the V bombers but also as the warhead for the Blue Steel stand-off missile and the Blue Streak ballistic missile, although Blue Streak was cancelled before it was deployed. 

Instruments have been described that employ (3-ray attenuation [10-15]. The aecuracy of these devices is limited by their sensitivity to changes in feed density [16]. In order to calibrate it is necessary to re-circulate slurry samples in a closed loop at a number of dilutions for each slurry system, sieve analyses being carried on representative sub-samples. The signals from a scintillation counter can be used to control mill feed rate in order to compensate for changes in feed ore, grindability and feed particle size. Accuracies of 2% to 3% have been reported on Cornish granite, nepheline systems and copper and iron pulps in the size range 20 to 105 pm [17,18]. 

Historically, many societies required that measuring devices be physically compared with and calibrated against official standards. Physical representations of measuring units were made as precisely as possible and carefully stored and maintained to serve as standards for comparison. In ancient Egypt, the standard royal cubit was prepared as a black granite rod and most likely kept as one of the royal treasures by the pharaoh s chief steward. That simple stone object would have been accorded such a status because... 

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