Gratings

R W Wood, in turned fruitwood casings

Three gratings made by R W Wood in turned fruitwood casings.

On one edge is written "Focus 180cm. R. W. Wood '98"

On each the three other grating edges are written...

• Zone plate

• Type B

• Phase reversal

One of the gratings appears to be a circular diffraction grating.

Diameters 6.5cm approx.

1898