Jean_LAMESCH_Sliderules_Collection_BOX_JL06

1677_BRL_RADIAC

1677_BRL_RADIAC

BRUNDELL RULE Limited (UK) sliderule for radiation exposure levels. The empirical law of decrease is of the type 7/10, i.e. after 7 hours radiation levels have decreased down to 1/10 of the original value (this is not the usual exponential decreasing law valid for a single isotope). Read this excellent "Doomsday" article here. Heavy plastic corpus, cardboard case.