![](https://coimages.sciencemuseumgroup.org.uk/29/324/medium_thumbnail_1925_0286.jpg)
Glass disc for telescope mirror
- maker:
- Charles Algernon Parsons
![Glass disc for telescope mirror, 12 diameter and 2 1/4' thick](https://coimages.sciencemuseumgroup.org.uk/311/879/medium_smg00028410.jpg)
Glass disc for telescope mirror, 12" diameter and 2 1/4" thick. Built up from two 3/8" plate glass circles separated by granulated glass in an experiment conducted by Sir Charles A. Parsons