A Medieval Pottery Kiln at Audlem,Cheshire

BUILDING ACCOUNTS for 1398–99 give detailed costs of the construction of a circular, brick, free-standing artillery tower. The artillery towers at Southampton and Canterbury were linked to existing wall circuits, and detached forts in France may be more comparable to the tower at Norwich.     

Own-child estimates of U.S. white fertility, 1886–99

Abstract

The collapse of empires is exceedingly difficult to understand. The author examined the distribution of imperial lifetimes using a data set that spans more than three millennia and found that it conforms to a memoryless exponential distribution in which the rate of collapse of an empire is independent of its age. Comparing this distribution to similar lifetime distributions of other complex systems—specifically, biological species and corporate firms—the author explores the reasons behind their lifetime distributions and how this approach can yield insights into empires.