The tungsten mineral wolframite was known in the tin mines of the Saxony-Bohemia region long before the element itself was discovered. The origin of the word is assumed to be derived from the German words "wolf, meaning beast of prey, and "rham", meaning froth. "It eats up tin as a wolf eats up sheep". The writers of the period before 1781 had vague ideas as to the composition of the mineral that they had named. Tin miners called the mineral "mock-lead", an ore containing iron, arsenic, tin and a nonmetallic earth, or glassy earth containing iron and tin.

The planarizing technique of materials lapping and polishing shows many benefits in providing samples for optical microscopy in failure analysis, quality control and related fields. A method is described below which provides both rapid and accurate micro-sections of pcb's, wafers, packaged components and other processed materials, with the use of a novel approach involving a 'calibrated' polishing base and a 'Micropositioner' head. Other benefits include the ability to halt material removal at a predetermined process endpoint and convenient sample mounting techniques.

Notwithstanding the importance of trees, considerable technical problems have severely restricted study of the fine structure of the vascular cambium and the wood and bark that it produces. And despite the advent of immunocytochemical techniques, it is only in the last few years that the roie of the cytoskeleton in the process of secondary vascular differentiation has been studied. Yet, for those who persist with this intractable material, the experience can be rewarding. This article discusses the difficulties involved in microscopy of this material, and offers some solutions.

An accurate calibration of magnification, diffraction patterns and the relative rotation between the two is critical in quantitative transmission electron microscopy (TEM). The manufacturers of TEM's supply magnification values for each image magnification step and each value of camera length for their instruments, but these values have been observed to be in error by up to 10%, These errors can occur due to variations in lenses in individual microscopes as well as through power supply variations and aging electronic components. Before attempting quantitative TEM analysis, a series of calibrations of the individual TEU should be undertaken.

I had recently been involved in a computer group discussion about the Warth in-Starry stain. No one seems to like to do it, except me. Here is a procedure that my histology laboratory (The Toledo Hospital, Toledo, Ohio) received from Lee Luna, who was a consultant to our laboratory, just before his death, Any "tips-of-the-trade" I have added.