Cold War Water Contamination Calculator No. 1

This calculator was produced by BRL Limited for the British government. It was designed by the Atomic Energy Research Establishment at Hartwell in England for issue to civil defence organisations.

The calculator is five inches [130mm] in diameter and consists of three plastic disks and a cursor. The one shown in the photographs was produced in 1963.

Water contamination calculator 1

Water contamination calculator 6

Water contamination calculator 7


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Atomic Atolls

The USA had two nuclear testing grounds during the early years of the Cold War. The Nevada Proving Ground was only 65 miles from Las Vegas. Most of the 928 tests of fission devices were under ground. The fallout from the 100 tests that were above ground [including the well named Dirt Harry test] are now believed to have caused between 300,000 and 600,000 cancer deaths in the USA.

Nevada Proving Grounds 51-92

Those are not molehills.

See this post for more information.

When the USA started testing fusion devices [hydrogen bombs] it needed to move to the Enewetok and Bikini Atolls in the Marshall Islands. The islands in the atolls already had names but most were difficult for Americans so each was given an alias.


Test shot Seminole of Operation Redwing, Bogon

Operation Redwing test shot on Bogon [aka Irene]


Ivy_Mike November_1952 elugelab flora

Flora [aka Elugelab]



The Umbrella test [part of Operation Hardtack] near Pokon [aka Irvin], Enewetak Atoll. An 8kt device detonated at a depth of 150ft.




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Nuclear Bomb Effects Computer sales brochure

Nuclear Bomb Effects Computer Lovelace V2 01

Nuclear Bomb Effects Computer sales brochure 1

Nuclear Bomb Effects Computer sales brochure 2

Note the price of $1.75 for one computer. Peter Sellers was seen using one of these in the Dr Strangelove film. I think they were also given away to people attending some of the early performances of the film.

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Chemical Agent Calculator

This calculator surfaced in Greece but is probably of US origin. No author information is shown but its reference number is 6LS-2820. Its purpose is to calculate the amount of a chemical agent required to saturate a target using a number of different delivery systems [e.g. 4.2″ mortar, howitser, rocket or 100 gallon airborne spray tank].

chemical agent 1

The back of the calculator refers to agent GB. That is the nerve gas Sarin.

The directions also refer to agent HD. This is mustard gas. Agent VX is the VX nerve gas. Under the UK’s Rainbow Code system VX had the code name “Purple Possum”.

chemical agent 2

The disk refers to the US Honest John and Sergeant missiles as possible delivery vehicles. Honest John was first deployed in 1953 [and remained in the NATO arsenal until 1985] but the M139 chemical weapon warhead was not available for the Honest John until the 1960s.

M139 warhead containing Sarin bomblets

The Sargeant missile was deployed in Europe from 1963.  A chemical weapon warhead option was considered but the development project was cancelled in 1970.

The calculator consists of three disks. The largest is made of card and is just under 5″ [125mm] in diameter. It is fairly crudely made compared to the very high quality Cold War calculators later produced by Perrygraf.

Please leave a comment if you have any more information on this calculator.

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Before and after a nuclear attack on the UK

A set of posters produced by the Home Office Civil Defence department in 1958. The posters showed the effects of a nuclear attack on British cities. The posters were printed by the Hydrographic Supplies Establishment and sold for one pound, seven shillings and six pence.

The posters are 29 inches by 23 inches.









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Nuclear war by accident

Eric Schlosser has a fascinating and frightening article [World War Three, by Mistake] in the New Yorker  which describes how close we came to accidental annihilation during the Cold War, and how close we are to it now.

When the US public see their military idiots prodding the bear by posturing around Europe and wingnuts like Senator John McCain describe Putin as “a thug, a bully, and a murderer” they might want to think about what will happen if things go wrong and they prod too much.

The photo below shows a Russian Voevoda R-36M2 missile being loaded into a silo somewhere in Russia. Each missile carries up to ten warheads and up to 40 penetration aids to overwhelm enemy defences. Russian missile technology is much superior to that of the US and their missiles have a greater throw weight than US missiles like the Minuteman.  That technical superiority is why the US has to buy rocket engines from Russia.

There are at least 46 R-36M2  complexes. Probably the US knows where most of  are and could destroy most of them in a first strike. I very much doubt if it knows where all of them are and could destroy them all. If even one or two of them got out of their silos the US would become a third world country with ten or twenty of its largest cities destroyed. Don’t worry though, US senators and military commanders would be safe underground when the warheads arrived. Nobody important would be harmed.


This post describes what would happen if a 800 kiloton warhead detonated over Manhattan.



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Marshall Islands Stick Charts

The people of the Marshall Islands used a number of techniques to help them navigate between their 29 atolls and 5 islands.  Such as following the seasonal navigation of birds, celestial navigation and noting the interferences in air and sea patterns caused by atolls. They might also have taken frigate birds with them. These birds will not land on the water as their feathers will become waterlogged making it impossible to fly. When the navigators  thought they were close to land they could release a bird, which would either fly towards land, or  return to the canoe if no land was in sight.

Doctor David Lewis’ ‘We, the Navigators: Ancient Art of Landfinding in the Pacific’ is the classic study of Pacific navigation techniques.

Probably most of the travel in the Marshall Islands took place between the islands in individual atolls. Bikini Atoll has 23 islands and the central lagoon is 229 square miles. Enewetok has 40 islands and a central lagoon 50 miles in circumference. Navigating even within a lagoon would not have been trivial.

Navigating between atolls would in most cases have been both difficult and dangerous. The area bounded by Bikini Utrik, Majuro and Ebon is 165,000 square miles. That is a lot of sea to get lost in. Travelling from Bikini to Enewetok involves a journey of 190 miles and if a navigator missed Enewetok it was a long way to the next land.


Navigators were important people who guarded their knowledge. They created stick charts to help them remember the direction of other atolls and the currents and swells that would affect their navigation. The charts consisted of sticks tied to create a frame and shells fastened to the frame to indicate atolls.

Some stick charts just showed [usually inaccurately] the direction and distance of some other atolls, like this 1884 specimen one from a Swedish Museum.


And this one from the Harvard University’s Peabody Museum.


Others also included sticks to indicate the flow of currents and swells.


Each navigator prepared his own stick chart and probably jealously guarded it from other navigators, just as sailing masters guarded the charts and notes in the early days of Western exploration.

During the Cold War the US used the Marshall Islands for testing nuclear weapons. The islands were designated as the Pacific Proving Grounds. See this post on the testing that took place there. There is also a stick chart that was made to illustrate the geography and identify the main atolls used for testing.


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