Faraday to Peter Henry Berthon   19 April 1860

Royal Institution | 19 April 1860

Sir

Several of the answers from the Lime light company¹, are not direct to, or sufficient for, the questions; I will briefly point them out.

2.6. “The nature of the gas fuel?” The quantity required in 12 hours?” - The answer has no reference to it but is about coke and oxygen[.]

2.7. “How is the gas fuel to be obtained? - How is it to be stored?” - The answer has no reference to the questions.

2.8. “What is its (the gas fuel) current price for 12 hours including materials, wages, repairs, and other current expences?” The word its in my query is written the in the company’s paper and may perhaps explain why the answer has no reference to the question.

2. 12. “What is the vertical height and horizontal width of the most intense part of the luminous object? and what the height of the part which may be called generally intensely luminous?” By luminous object I mean the whole cylinder of lime at the ignited part:- and being three inches in diameter or about 9½ inches in circumference I conclude, by the answer, that there are in that circumference, six spots, half an inch wide, of most intense ignition;- that these being surrounded by less ignited parts may be considered as extending to an inch in width;- and that there are six intervening dark portions, each between 0.6 & 0.7 of an inch wide.

2. 16. Asked whether there are any exceptional cases such as the Needles Eddystone, Bishops &c &c These (by the answer) do not seem to be known. Reference is made to the convenience of storing, building, &c and the exceptions are said, if any, to be where these conveniences do not exist.

2.18. Relates to outfit. The answer seems to imply that the Fresnel apparatus would be dispensed with and gives no estimate on that point.

Supposing these answers had been to the purpose, or that direct answers may now be supplied, there comes the point, how far will they be justified and sustained in practice. At the close of the company’s letter, it is not doubted, that, the directors will obtain permission to exhibit their light in a lighthouse, subject to the rules and regulations of the Trinity Corporation. My letter, containing the enquiries (8 Feb 1860²) did not go so far as that, as you will see at the end:- for it requires full proof of the fitness of any proposed arrangement, before considering its introduction into a lighthouse: and says that any failure in such preliminary proof, or any serious departure in the results from the answer given to the questions, will be considered as showing that the proposed application has not been sufficiently matured &c. I see no reason at present to alter that course as far as I am concerned in watching the matter³[.]

I have the honor to be | Sir | Your Very Obedient Humble Servant | M. Faraday

P.H. Berthon Esqr | &c &c &c

Endorsement: No 1933 | Universal Lime Lt | Professor Faraday:- reporting upon answers to Questions submitted by him; returning them. (enclo:) | 19 Ap: 1860. | Ent in book on Scientific Reports (folio) 353 | Board 27 April 1860