Disney, Hill and Baker in their 1928 booh on the Origin and Development of the Microscope, quote the 1829 article on Optics of the London Encyclopedia as saying; “Microscopes, though but toys compared with telescopes, nevertheless deserve to be rendered as perfect as possible; for they yield not to them in the quantity and variety of rational amusement which they are capable of introducing to us (though not of the sublime description of the wonders of the heavens). Compound microscopes, though not so much to be depended upon for the purposes of discovery and philosophical investigation as single lenses, are still the best adapted for recreation”. It is hard to imagine that this was written at about the time when Robert Brown of motion fame, was discovering the celt nucleus (1831), the repository of the genetic code and thus arguably laying the foundations for all of modern biology. The sentence quoted might be taken to suggest that there was no evolutionary connection between hand lenses and compound microscopes, since as late as the 1830s the two still competed.

In trying to follow the evolution of microscopes it is trite to state that lenses had to come first. It was known for a long time that objects seen through a glass bulb full of water appeared enlarged, but the water was thought the important factor and it was not until the time of Alhazen (962-1038) that the action of a lens was understood. Roger Bacon (1242-1292) wrote “if one looks at letters and other minute things though the medium of a crystal or glass or other lens put over the letters... he will see the letters much better and they will appear much larger to him... and therefore this instrument is useful to old men and to those having feeble sight” Spectacles seem to have been invented by Salvano d'Aramento degli Arrtati of Florence who died in 1317, the secret process of how to make them being revealed by a contemporary, Alessandro della Spina of Pisa. The use of lenses in visualizing small objects made slow progress at first but eventually led to “macroscopy”, in the form of spectacles and then to microscopy.

Developments in space exploration, microelectronics, and other high-tech industries have promoted cleanroom technology and increased the need to identify particles sometimes too small to handle with the polarizing light microscope. Light microscopy has traditionally been the most commonly used technique for small particle identification and many microscopists are very proficient in identifying particles using a polarizing light microscope as the principal investigative tool. The polarizing light microscope, in the hands of a good microscopist, is an extremely efficient instrument for particles down to a few micrometers in size. However, in the size range below 5 pm, an instrumental approach to small particle identification is essential. The development of electron microbeam instruments in the early '60s and 70s introduced a new dimension to small particle identification. In these instruments, particles of 1 urn and smaller can be chemically identified when chemical characterization of particles is combined with cathodoluminesence and a relatively simple optical characterization in the instrument itself.

A confocal laser scanning microscope which can collect images in both transmission and reflection modes has been installed and is being tested in the Imaging Laboratories of the John P. Roberts Research Institute, London, Ontario. Designed by Dr. Ted Dixon at the University of Waterloo, it is being developed by a multi-disciplinary research group which includes the Ontario Lasers and Lightwaves Research Centre and the Department of Physiology, University of Toronto; the Radiology, Physics, and Pathology Departments, MacMaster University; and the Zoology Department, University of Western Ontario.

Commercial confacal microscopes operate by reflectance or epifluorescence. A pair of scanning mirrors direct a diffuse laser beam in a raster pattern through an objective lens, which focuses it on the specimen. Reflected light passes back along the same light path, being “de-scanned” by the moving mirrors and then diverted by a beam splitter into a detector. On its return to the detector, light from the focal plane is focussed through a pinhole, which blocks light from out-of-focus regions of the spectrum The microscope stage is moved up and down by a stepping motor to collect images at different depths.

Our attention was caught by a recent article in this newsletter (Issue #7, September, 1992) entitled “Modern Microscopy on the Light Side. The FTIR Microscope” by Mr. Skip Palenik. Mr. Palenik makes some cogent points but we feel there is a bit more to the story. We are spectroscopists by training and experience and “...have done some reading and/or taken a short course...”, but we have not “...set ourselves up as microscopists...”, at least so far. We have, however, for the past nine years attempted to educate microscopists, spectroscopists. chemists and even non-scientists regarding the benefits of combining optical microscopy and molecular spectroscopy. We are convinced the whole is greater than the sum of the parts.

The very rapid acceptance of infrared microspeetroscopy by the analytical chemistry community reflects its power to solve diverse problems. One of the long time characteristics of infrared spectroscopy has been that its users vary greatly in their needs and thus in the sophistication in their systems. In connection with this, it must be realized that the fundamental laws of physics prevent the coupling of a microscope and an infrared spectrometer, in such a way as to optimize the performance of both, at a cost which can be borne by all users. As a result, some infrared microscopes have "been optimized for viewing capabilities while compromising spectroscopic capabilities and vice versa. Such compromises are not unusual in the field of infrared spectroscopy and the advantages gained by them constitute part of the reason for such widespread use of infrared in chemical analysis.