R Institution^<1>

My dear Sir

I do not know of Hares Experiment^<2> We have no flat coil of copper: but perhaps an Electromagnetic coil would do.^<3> When you pursue your subject you can try such as we have and also the spiral tube – I should not expect much from either process: the latter you cannot put into the focus of a lens or mirror as you can the former i.e. the single spark

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 the lighthouses collects ⅔or even ¾ 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 my 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

1. Royal Institution, London.

2. Robert Hare (1781–1858) Professor of Chemistry at the University of Pennsylvania Medical School. WHFT describes Hare’s experiment for increasing the brilliance of the spark of a Leyden jar in Doc. No: 06429 15 giugno 1851.

3. This would be a coil cylindrical in shape, rather than flat.