Faraday to James Timmins Chance   14 September 1860

Royal Institution | 14th Septr. 1860

My dear Sir

I caught the Deputy Master¹ to day and advanced matters[.]

You will receive a letter at once authorizing you. &c &c

The Trinity house (by desire of the Board of Trade) ask me for a general estimate of expence of the experiments I am making;- and so I have to ask you:- as it must be charged separately from the service of the lighthouse. I think all I did with you & all we shall have to do at Whitby in the first instance may be considered as experiment:- except perhaps the lamp; which if it remains permanently, will be charged to the lighthouse. - Can you send me an idea of a general sum; about &c[.]

In the mean time you can go on with the alterations at the Whitby South lighthouse:- but the Deputy Master will not be ready to visit it with the Commission before Wednesday the 3rd of October, - because of the Queens visit to the continent² &c. I shall want to see it a couple of days before hand[.]

The North light to remain untouched either as to lamp or adjustment[.]

The South light

To have a good lamp - raised so that a point in the axis 28mm above the burner shall be in a line passing through the center of the lenticular band to the sea horizon - the chimney of the lamp to be six feet high from the bottom of the glass[.]

To adjust the lower reflectors of all the octants alike to the sea horizon;- namely by a focus 20mm above the burner & 50mm from the axis towards the reflectors[.]

To adjust the four octants of upper reflectors also to the sea horizon but from different foci - there being for the most Northern octant 20mm above the burner[.]

and - 30- from the axis

for the next toward the South, 28mm up

and 30- aside from axis

for the third - 30³mm up in the axis

for the most southern octant

28mm up

and 40- aside from the axis

We must have the French Focus in so that I have left

the 20mm up and

40- aside - out

I think I have mentioned all the points.

Ever your truly Obliged | M. Faraday

Jas. Chance Esq | &c &c &c