NG5 eyepiece reticles, Fairs

Fairs - NG5

Designed to extend the sizing range of globe and circle graticules.

Example: Used in conjunction with NG2 the overall size range = 128:1. The circles increase by 2.

Note: Both graticules would have to be used with the same microscope, eyepiece and objective.

The use of the eyepiece graticules shown in this section makes it possible to analyse specimens containing particles as an alternative, or in addition to, sieving. Graticules for particle size analysis are particularly popular when there are only limited quantities of particles or where particles are smaller than 50 microns in diameter. Typical substances analysed are sand grains, soil particles, plant seeds, fertilisers, abrasives, liquid droplets, pigments, pulverised coal, silica, fibres, and fine dust.

The basic principle employed is to compare particles to the globes and circles of varying sizes that appear on the graticule - dark particles being compared to solids globes, and light or transparent ones to the circles. Naturally the procedure varies with the graticule concerned, more information about which is given below.

Please note that for calibration, the circles and globes will represent particles smaller in diameter by the magnification of the objective.