Old Bausch & Lomb Electric Microscope or Micro-Projectors in History and Pictures
By Larry Brian Radka
Micro-projection (with Microscope or Micro-projectors) contributes greater ease, simplicity, and effectiveness to many tasks involving group study, or examination, of microscopic materials. Micro-projection adds immeasurably to teaching efficiency and insures valuable timesaving in group consultation and demonstration. Providing a visual focal point for all participants, it promises free and easy discussion of the various details of the specimen under study.
There is complete understanding between instructors, scientists or lecturers and their audiences when micro-projection is used, for they can visibly point out the features of real significance in a specimen. There is not time lost in studying details that appear more striking but have little meaning. The importance of this cannot be emphasized too strongly, especially in the medical field where time and accuracy are often of the utmost urgency. Micro-projection provides the best and most economical method of maintaining adequate instruction facilities when budget limitations preclude heavy investment in microscopic material. By eliminating the need to purchase large numbers of identical specimens, a greater variety can be provided.
Schools find micro-projection a quick, effective method for instruction in the general sciences that deal with microscopic materials. It serves as preliminary instruction for students who intend to major in one of these sciences, so that they can go to their own microscopes with greater interest and confidence because they already know what they should look for.
Microscope or Micro-projectors have always provided a considerable saving in time and money, so some pictorial and informational history on the subject is worthwhile considering here in relation to its previous use in photography.
The electric microscope or micro- projector probably first appeared at some point in antiquity, after the Egyptian priests and others had discovered the carbon arc light. However, this technology was apparently lost at some time during the Dark Ages, and did not reappear until the nineteenth century. The is evidenced in a report in the October 1870 issue of Harper’s New Monthly Magazine, which expounded on the electric arc light’s camera-friendly merits in conjunction with the use of the microscope in the United States. In an article therein, entitled “Electric Light in Photography,” the writer informs us that
“Among the most interesting communications made before the American National Academy of Sciences, at its last meeting, at Washington, in April, was one by Dr. Woodward, of the Army Medical Museum, in regard to the use of the electric light in photography. Occupied for many years in the preparation of photographic negatives of microscopic objects, the author experienced great inconvenience from the difficulty of working at times when the sun did not shine sufficiently for his purposes; and, after trying various kinds of artificial illumination, he finally came to the conclusion that the electric light, under some circumstances, was to be preferred even to the sun itself, since photographs could be taken at any time of day or night, and after a much shorter exposure than to the sunlight. The magnesium light was found to have some advantages, especially when the object was not to be magnified more than one thousand times; but for average work, especially under very high powers, the electric light was found to surpass all its rivals.
“The apparatus used was a Duboscq’s lamp kept going by a battery of fifty small Grove’s elements. Seven and a half pounds of strong commercial nitric acid, with three of sulfuric diluted with ten times the quantity of water, were sufficient to charge the battery and keep a continuous light for three or four hours, during which time from twelve to thirty or more photographs could be produced, the number varying with the character of the subject and the amount of preparation required. Dr. Woodward states that for a negative of one thousand diameters, about thirty seconds are sufficient for some objects, while for others about three minutes were required. This light was found to be perfectly adapted for producing photographs of the soft tissues with any power under a thousand diameters.”
In the nineteenth century, Bausch & Lomb substantially improved on the design of the Woodward's battery-powered carbon arc micro-projector used for photography, as my micro-projector above and the old 1925 Science magazine advertisement below verify.
In case you can't read the description in the advertisement above, it runs as follows:
"The New Bausch & Lomb Compact Micro-Projector Permanently Aligned . . .
THIS new instrument has been designed to meet the demand for a compact and permanently aligned Micro-Projector. All optical parts are accurately precentered and are vertically and laterally aligned. The only centering adjustment necessary on the part of the user is to bring the light source (either a Mazda unit or an Automatic Feed Arc Lamp) into alignment with the optical axis. This adjustment is easily made by two screws on the rear of the illuminating unit support.
The substage is arranged with three condensers and a heat absorbing filter glass. The condensers—on swinging arms—take care of a range of objectives from a 72 mm Micro-Tessar to a 4 mm objective."
This projector, unlike Woodward's battery-powered micro-projector, could be powered by either commercial DC or AC as the label on its Automatic Feed Arc Lamp above indicates.
Also, the B & L arc lamp incorporated a mechanical wind-up clock mechanism to automatically maintain the proper distance between its blazing carbons for several hours at a time.
For much more on carbon arc lights, see The Electric Mirror on the Pharos Lighthouse and Other Ancient Lighting.
This page was last modified on Monday, February 01, 2010