When one speaks of microscopes one usually imagines devices which produce spatially resolved images. So it is most intriguing when a novel application of microscopic techniques permits discoveries not by forming images but by allowing very precise measurements to be made on very small objects. The blind showing the way to the sighted! A recent paper in Nature is a good example of what I speak. It deals with biological motors, which, as cell biologists are learning, are involved in the movement of cells and the movements of organelles within cells. There are a number of different biological motors, but all are molecules which change shape, as they convert the chemical energy derived from the hydrolysis of high energy molecules such as ATP, into mechanical work. As the motor molecules undergo this conformational change and then return to their original state they take a step away from their starting point, dragging along the structures to which they are attached.

The study of plant morphology and plant cells in the scanning electron microscope is often compromised by the limitations of specimen preparation techniques. Air drying usually results in unacceptable shrinkage and distortion of the normal surface morphology of plant cells. Chemical fixation followed by critical point drying or chemical drying using fluorocarbon compounds improves morphological results but still imparts artifacts, adds chemical constituents to the specimen, and requires the use of toxic chemicals, a hood, and much time.

One technique that eliminates many of these disadvantages and is even suitable for specimen preparation in the field is tissue printing. For easy, quick recording of stem anatomy and collection of cell exudates for subsequent analysis, its “elegant simlicity” is compelling. Historically, the application of tissue printing has been in connection with optical microscopy. However, this technique works very well for SEM and associated elemental characterization of residues by x-ray microanalysis. The tissue print technique applied to SEM is much the same as for optical microscopy.

I bought my last useful pocket calculator in 1975 and I still use it regularly. Every time I pick it up I know how to use it, since all the functions I need are printed on its buttons, and I expect to be using it when I retire, if I can still get the batteries. My son bought a “more sophisticated” calculator for his A-levels in 1988 and I inherited it shortly thereafter, it lies in my desk drawer but I cannot use it because it offers so much more than I need and there is too much printed on and around each button. I would need to read the manual every time I wanted to use it. On the desktop close by sits my telephone: It has 46 buttons and a 17-page manual and offers an enticing array of facilities. Unfortunately I only need each of these “facilities” about once a month and have never been able to memorize the necessary procedures. As a result all I can do is answer it when it rings and dial out.

The presence of internal boundaries can significantly influence many important properties of materials, such as fracture toughness, creep, electrical conductivity and magnetic behavior. Interfacial structure, chemical composition and bonding, on a nanometer length scale, are often controlling and sought after factors influencing these properties. An electron spectroscopic technique, known as energy-loss near edge structure (ELNES) analysis, can be utilized to probe compositional and bonding variations with a spatial resolution less than 1 nm and is therefore well suited to this endeavor.

When a fast electron passes through a material in an electron microscope, it collides with the electrons bound to the atoms in that sample. As a result, the fast electron often gives up a small fraction of its kinetic energy to the bound electrons. The laws of quantum mechanics dictate that these so-called inelastic scattering events will only take place if the bound electron can gain enough energy to enter an empty energy level.