Suggest how a voltmeter with a strip of mirror mounted under the needle & near the scale may help to reduce errors when taking a reading?

In instrument like a voltmeter, because of the small
distance between the scale and point of needle directly above the scale, the needle
appears to point to different points on the scale when viewed from different directions.
For taking accurate readings the position of needle must be observed from a point which
is vertically above the position of the needle.

A mirror
mounted under the needle and near the scales of an helps take more accurate readings by
enabling the observer to locate the point on the scale that is directly under the needle
showing the reading. To do this this the observer looks at the voltmeter from a position
at which the needle completely hides the image of the needle in the mirror. The observer
then notes down the point on the scale that the needle covers points to from this
direction of viewing the scale.