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Psyche 
[June 
We find that even greater flexibility of use is possible if the micro- 
scope is attached to a rod carried on a photographic focussing rail 
rather than one directly attached to a tripod head. With an extra- 
long focussing rail (45 cm, for instance) it is possible to put the 
tripod down once, close to the subject, and be sure that enough 
focussing range is available to bring the subject in focus without 
again moving the tripod. This can be critical in circumstances 
where movements of the vegetation in which the tripod is standing 
can cause the subject to flee or cease normal activity. 
Using the device requires practice. A wide variety of adjust- 
ments are available through the pan-and-tilt head of the tripod, 
and through the rack-and-pinion of the focussing rail and micro- 
scope focussing system. Use of a tripod with an elevator head 
that is reversible further extends the scope of the device. Depth 
of field is slight even at very low powers of the microscope but con- 
tinual focus adjustment is not difficult or distracting. Viewing 
with one’s hands resting on the focussing wheels of the microscope 
helps one to acquire a habit of keeping a moving object in focus. 
It is possible to use one eyepiece for viewing and have a camera 
permanently attached to the other. This helps immensely in ob- 
taining action photographs of transitory behavioural events. 
References 
Robinson, M. H., and Robinson, B. 
1972. Techniques for the observation of spider behaviour. Bull. Brit. Arach. 
Soc. 2:58-59. 
