The elements of bacteriological technique : a laboratory guide for medical, dental, and technical students / by J.W.H. Eyre.

  • Eyre, John W. H. (John William Henry), 1869-
Date:
1913
Catalogue details

Licence: In copyright

Credit: The elements of bacteriological technique : a laboratory guide for medical, dental, and technical students / by J.W.H. Eyre. Source: Wellcome Collection.

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    vision, special eyepieces are also obtainable having a sledging adjustment to the eye lens for focussing the micrometer. The value of one division of the micrometer scale must first be ascertained for each optical combination by the aid of the stage micrometer, thus: 1. Insert the eyepiece micrometer inside the ocular and adjust the stage micrometer on the stage of the microscope. 2. Focus the scale of the stage micrometer accurately; the lines will appear to be immediately below those of the eyepiece micrometer. Make the lines on the two micrometers parallel by rotating the ocular. 3. Make two of the lines on the ocular micrometer coincide with those bounding one division of the stage micrometer; this is effected by increasing or diminish- ing the tube length; and note the number of included divisions. 4. Calculate the value of each division of the eye- piece micrometer in terms of [x, by means of the fol- lowing formula: x= 10 y. Where x == the number of included divisions of the eyepiece micrometer. y = the number of included divisions of the stage micrometer. 5. Note the optical combination employed in this experiment and record it with the calculated microm- eter value. Repeat this process for each of the other combina- tions. Carefully record the results. To measure an object by this method read off the number of divisions of the eyepiece micrometer it occupies and express the result in micra by a refer- ence to the standard value for the particular optical combination employed.