Joseph Guyton
1862, 10 November
Cloud formation 20 miles from Alexandria, November 10th 1862, S. W. wind at 6 pm.

Photograph
Wellcome Collection
Wellcome Library, Creative Commons Attribution (CC BY 4.0), cmydknhg
 
A.Alpha particle strikes helium nucleus and they part at right angles. B. Alpha particle enters nitrogen which ejects proton and becomes nitrogen. Experiments by Blackett in a Wilson Cloud Chamber.
 
LL/92923