Mr. J. Eric Marson has for many years been one of the most dedicated people in the UK in teaching Amateur Microscopy and helping both the novice and amateur grow their skills. His small business, Northern Biological Supplies, has provided material and accessories for many years. His personal contribution to this hobby has been staggering. Eric has written a range of booklets which are perfect for anyone wanting to get started or wishing to learn more about Microscopy at an amateur level. He has kindly contributed extracts from one of the booklets here. I strongly recommend that you write to Eric Marson for further details of the booklets he has to offer. Booklets 1 to 17 have been bound to form a complete work called Practical Microscopy which will enable the newcomer or novice to become a skilled amateur microscopist without reference to any other instruction. The booklet is written in a easily read format and is professionally presented. Details The Editor
The following 'extractions' from Eric's booklets have been edited or shortened to preserve space. The information contained in the original work is more comprehensive.
Select from below or scroll down to read each one...
Using your microscope
Specimens are examined by putting them onto a glass microslide, and covering them with a thin cover glass. If the specimens are dry and thick, a cover glass may not be necessary. Details of the best way are given for many specimens, in the following pages, but in each case the specimen is placed centrally on the microslide, and then examined by putting the microslide on the stage of the microscope. The microslide is put with the ends under the stage clips so that it will not move, unless you wish to move it. When the microscope is focussed correctly, a clear magnified image of the specimen should be seen.
The specimen will only be seen if the light passing through it, or reflected from it, travels up the tube of the microscope, to the eyepiece, and into your eye.
Illuminating from below
Usually specimens are examined by passing light through them. This light may be either from a mirror, or from a bulb under the stage of the microscope. A specimen must be fairly transparent to be examined in this way, and specimens, or parts of specimens, which do not allow light through them, will appear as dark areas in the field of the microscope. The mirror may be used to reflect either daylight or light from a lamp, but in each case it will be necessary when setting up your microscope, to move the mirror on its pivots, until the field of the microscope is evenly illuminated.
Illuminating from above
If an object is opaque, and will not allow light to pass through it, the microscopical details of the surface may be seen by shining light onto the specimen from above. This may be done by shining light from a torch or lamp, onto the stage of the microscope, or by allowing sunlight to fall onto the stage. The image seen, will not be as bright as when illuminated from below, because you will only see the parts which reflect the light, and the field of the microscope will appear quite dark. Transparent specimens often also show interesting details when examined in this way.
This method of illumination should not be used with high magnification objectives.
The magnification of your microscope
The magnification may be given in a leaflet supplied with your microscope, or may be marked on the microscope itself. Usually however the eyepieces and the objectives are marked individually with their magnification, or in the case of objectives, with their focal lengths in fractions of an inch. Total magnification is calculated by multiplying the magnification of the objective by that of the eyepiece, thus:-
x4 objective with a x5 eyepiece = x20 Total Magnification. x40 objective with a x10 eyepiece = x400 Total Magnification.
Using different magnifications
Suggested magnifications to be used when examining specimens are given in the following pages, but specimens should always be examined first under low magnification, followed by higher magnifications. Any interesting specimen or part of a specimen should be placed centrally in the field of the microscope, by carefully moving the microslide, and then holding it in this position with the stage clips. A higher magnification can then be obtained by rotating the nosepiece of the microscope, until a higher magnification objective clicks into position. With low magnification objectives, the coarse focussing adjustment should be used, and with a high magnification objective, the fine focussing adjustment is most suitable. If your microscope has only one focussing adjustment, you will have to be very careful when focussing with a high magnification objective in position.
Looking at everyday things
In booklet 1 available from NBS, you will find details of the way to use your microscope so that you can find out more about the microscopy and structure of a number of very common things.
For each specimen you will find details of the apparatus which you will require, details of of the simple preparation which is necessary before specimens can be examined under the microscope, and also descriptions of what you will see. Drawings have not been included, but a plain margin has been left at the side of each page, so that you can make your own drawings and notes on what you have seen. All the preparations described in this booklet are temporary ones, and after they have been examined, the microslides and cover glasses should be cleaned and washed in detergent solution, so that they may be used again. Details of the ways to make permanent mounts are contained in later booklets in this series. by J.Eric Marson
Booklets 1 to 17 are bound in a single book called: Practical
Microscopy. It is available at low cost from Northern
Biological Supplies, 3 Betts Avenue, Martlesham Heath, Ipswich,
IP5 7HR. England. Tel: UK 01473 623995. Please write or phone
for order details. Also can be ordered on-line from
Microscopy UK; follow the 'Shop' button on Front Page link below.
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