La Mettrie and charlatanism: The dynamics of recognition and denunciation

This paper contributes to a genealogy of charlatanism by tracing two figures which eventually come to overlap: the street charlatan or operator, known for his eloquence and deceptive skill, and the comically incompetent doctor, represented classically in France in the theatre of Molière. The paper argues that eighteenth-century France gives the term 'charlatan' new moral weight while extending it to fields outside medicine, most notably to philosophy. Some examples of the denunciation of charlatans are examined, and it is suggested that denunciation was usually both extensible and reversible. La Mettrie appears in this regard as the very type of the denouncer denounced. He was a doctor-philosopher who vigorously decried the Paris Faculty of Medicine as a group of charlatans, even though his own medical qualifications were anything but impressive, and he was in turn reviled by Diderot as the most charlatanic and unworthy of philosophers.

Atmospheric corrosion of copper and the colour, structure and composition of natural patinas on copper

This paper describes the results of atmospheric corrosion testing and of an examination of patina samples from Brisbane, Denmark, Sweden, France, USA and Austria. The aim was threefold: (1) to determine the structure of natural patinas and to relate their structure to their appearance in service and to the atmospheric corrosion of copper; (2) to understand why a brown rust coloured layer forms on the surface of some copper patinas; (3) to understand why some patinas are still black in colour despite being of significant age. During the atmospheric corrosion of copper, a two-layer patina forms on the copper surface. Cuprite is the initial corrosion product and cuprite is always the patina layer in contact with the copper. The growth laws describing patina formation indicate that the decreasing corrosion rate with increasing exposure time is due to the protective nature of the cuprite layer. The green patinas were typically characterised by an outer layer of brochantite, which forms as individual crystals on the surface of the cuprite layer, probably by a precipitation reaction from an aqueous surface layer on the cuprite layer. Natural patinas come in a variety of colours. The colour is controlled by the amount of the patina and its chemical composition. Thin patinas containing predominantly cuprite were black. If the patina was sufficiently thick, and the [Fe]/[Cu] ratio was low, then the patina was green, whereas if the [Fe]/[Cu] ratio was approximately 10 at%, then the patina is rust brown in colour. The iron was in solid solution in the brochantite, which might be designated as a (copper/iron) hydroxysulphate. In the brown patinas examined, the iron was distributed predominately in the outermost part of the patina. (c) 2005 Elsevier Ltd. All rights reserved.