(4) To bring an object into focus, watch from the side and use the coarse
adjustment to lower the objective until it is below the point at which the object would
normally be expected to come into view.
To avoid damage to slide or microscope, view from side for preliminary
focusing. Then, using the coarse adjustment and at the same time looking
through the ocular, raise the objective very slowly until the field comes into
view. Further adjust to the best image, using only the fine adjustment.
(5) In focusing upward with the fine adjustment, the object will first appear in
faint outline, then gradually more distinctly, and finally, sharply defined. If the
adjustment goes beyond the point of sharp definition, return to the point of greatest
clarity by using the fine adjustment.
(6) Never move an objective downward while looking through the eyepiece.
When the objective is moved downward, always observe the downward motion with the
eye held level with the microscope stage. Failure to observe these precautions can
result in damage to the lens of the objective or the object under study.
e. Care of the Microscope. The microscope is an instrument of precision with
many delicate parts, and it must be handled with the utmost care. Care should not be
confined to the optical elements alone. The microscope is a combination of optical and
mechanical excellence, one complementing the other. The following precautions should
always be observed in the care of the microscope:
No unauthorized person should manipulate the microscope.
(2) Keep the microscope as free from dirt and dust as possible. Dusty
lenses produce foggy images, while dust in the focusing mechanisms causes excessive
wear of those parts.
(3) The microscope should be always covered when not in use.
(4) Care should be taken to prevent all parts of the microscope from coming
into contact with acid, alkali, chloroform, alcohol, or other substances that corrode metal
or dissolve the cementing substance by means of which the lenses are secured into the
objectives and oculars.
Always carry the microscope with two hands by the arm and base.
Avoid sudden jars I such as placing the microscope on the table with
(7) No dust should be permitted to settle on the lenses nor should the finger
come in contact with any of the surfaces.
(8) The lens system should never be separated, as the lenses are liable to
become decentered and dust can enter.