interchanged are explained simply in this way.
| Screens employed | Thickness in mms. | Current observed |
|---|---|---|
| Aluminium | 0·01 | |
| Cardboard | 0·005 | 17·9 |
| Cardboard | 0·005 | |
| Aluminium | 0·01 | 6·7 |
| Aluminium | 0·01 | |
| Tin | 0·005 | 150 |
| Tin | 0·005 | |
| Aluminium | 0·01 | 126 |
| Tin | 0·005 | |
| Cardboard | 0·005 | 13·9 |
| Cardboard | 0·005 | |
| Tin | 0·005 | 4·4 |
111. Secondary rays produced by β and γ rays. An examination of the amount and character of the secondary radiation emitted by various substances, when exposed to