R Institution
16 June 1851
<1>
I do not know what mirror you used but I should have thought that a deep one would answer better than a shallow one. Such as they use at lighthouses collects 2/3 or even 2/4 of the rays which issue from the light in the focus.
There is no occasion for any one to think much for you for you are well able to think your own thoughts to an end. For mt part the moment I can get clear of the run of ordinary business all my thoughts will be given to the Magnetism of Oxygen.
Ever Truly Yours
M Faraday.
Notes:
1. Frank James 4/2438.
2. . See Doc. No: 6431