Thomas Stevenson to Faraday   8 July 1859

Dear Sir

I lately discovered by accident an erroneous date at page 35 of my volume on Lighthouse Illumination1, as to the early history of lens Lights. This date was given on the authority of papers in the Edinburgh Transactions2 & Phil. Journal3. Although the mistake has no reference to any of my own improvements it nevertheless materially affects the relative claims of others and I have therefore considered it to be only justice to them to cancel the remaining copies of the book still on hand and to substitute a corrected issue4. If you will be so good as to leave out the copy which I lately took the liberty of sending to you5 one of the new issue will be given in its place.

I hope that your labours in connection with the electric light may be soon crowned with success. I imagine however that where the flame is so small it would be necessary to employ the spherico-cylindric Lens which I proposed in the volume on Lt. H. illumination for increasing the duration of the flash in Revolving Dioptric Lights. By grinding the back of a common annular lens I think any amount of divergence could very easily be secured without taking it to pieces.

Trusting you will excuse this trouble

I remain | Dear Sir | Yours faithfully | Thomas Stevenson

Edinb. July 8 1859

Dr. Faraday | &c &c

1
Stevenson (1859a), 35 noted “So far back as 1812 Sir David Brewster suggested most important improvements in the illumination of lighthouses … . Though the earliest improvement with which I am acquainted, it is in some respects the most perfect”.
2
Brewster (1827).
3
Brewster (1823).
4
Stevenson (1859b). On p.35 he noted the error and withdrawal of the first issue and in the text replaced the sentences quoted in note 1 with “In 1823 Sir David Brewster published in the “Edinburgh Philosophical Journal” a design for lighthouses [Brewster (1823)], which is in some respects more perfect than those which are to be afterwards mentioned. He originally proposed this optical arrangement for burning in 1812”.

Bibliography

BREWSTER, David (1823): “On the Construction of Polyzonal Lenses and Mirrors of great magnitude, for Light-Houses and for Burning Instruments, and on the formation of a great National Burning Apparatus”, Edinb. Phil. J., 8: 160-9.

BREWSTER, David (1827): “On the Construction of Polyzonal Lenses, and their Combination with plain Mirrors, for the purposes of Illumination in Light-Houses”, Trans. Roy. Soc. Edinb., 11: 33-72.

Please cite as “Faraday3615,” in Ɛpsilon: The Michael Faraday Collection accessed on 29 April 2024, https://epsilon.ac.uk/view/faraday/letters/Faraday3615