GUTENBERG'S INKS AND PAPERS: NON-DESTRUCTIVE COMPOSITIONAL ANALYSES BY PROTON MILLIPROBE

Particle induced X-ray emission (PIXE) has been used in analysis of ink and paper of the 42-line Bible and other early printed works. Results are reported and their significance discussed.     

Some Extensions of Mills's Method for Urban Population Density Gradient Estimation

This paper extends Milk's method for estimating urban population density gradients to general noncircular and asymmetrical urban forms, using Gauss-Legendre quadrature embedded in a Newton-Raphson root finding algorithm. We also examine the sensitivity of the Mills method to measurement errors in the assumptions. Several issues arising from the comparison of analytical, Mills type estimation procedures with statistical procedures are explored, particularly in light of recent work that questions the negative exponential formulation of urban density gradients. We note in particular the influence of secondary population centers as a source of estimation bias.