Peter Henry Berthon to Faraday   17 November 1859

Trinity House, London, E.C., | 17th November, 1859.

Sir,

The Elder Brethren are desirous of your opinion on various points connected with a Fog Bell, which is to be placed on the Start Point, about 30 yards seaward of the Light House and about 76 feet above the level of the Sea.

I herewith enclose a rough outline of the proposed method of suspending the Bell, and also one which will shew the direction in which it is chiefly desirable to throw the sound.

The First Question is, whether a Sounding Board placed over the Bell and one in its rear (i.e. on the land side of it) might not tend to increase the sound in the desired direction, - and if so, secondly, whether the sounding Board should be of wood or iron. The perishable nature of wood renders iron preferable, if it is likely to prove as efficient in throwing off Sound.

Thirdly, in case you recommend iron, whether there would be any disadvantage in making use of corrugated iron, as being lighter and less liable to bend.

Fourthly, it is proposed to slope the platform beneath the Bell, do you think any advantage would be gained by covering the slope with metal plates in the direction the sound is to be projected.

The size or rather weight of the Bell, whose sound in fogs ought to be heard 3 miles, is another point on which we should be glad to have your advice.

The Bell will be struck by weights or hammers, working on the Ball and Socket Plan at either end of an iron bar, which will be made to revolve by Machinery.

The Revolving Apparatus will be protected from the weather by a house in the rear of the Bell, one end of which will be formed by the sounding boards, as shewn in the Drawing.

These are the chief points the Elder Brethren will be glad to have your opinion on, but any other general observations will also be gladly received.

I am, | Sir, | Your most humble Servant, | P.H. Berthon

M. Faraday Esq. F.R.S. | &c &c &c