Faraday to Alfred Austin   12 May 1860

Royal Institution, 12 May 1860.

Sir,

In obedience to the wishes of the First Commissioner of Her Majesty’s Works¹, &c., I yesterday examined the places at the Houses of Parliament where Mr. Daine’s process (as I was informed by Mr. Fincham²) had been applied³; these consisted of three small surfaces on the terrace, done in 1854; the upper part of the walls in the Commons’ inner court, done in 1854; the wall in the Peers’ inner court, done in 1856; two turrets on the river front, done in 1856; and a window near the Victoria Tower, done in 1856.

I am told that Mr. Daine’s application consists of oil and sulphur: as regards the oil, this agrees with what can now be observed; of the sulphur I could find no trace. The composition can still be found in places, such as the walls of the Commons’ inner court and the turrets. It occurs, occasionally, in patches, which have run down the walls, and also in tears resulting from such flow. These tears, though black on the outside, are soft, and when squeezed, the yellow thickened but unsolidified oil flows out. I find no sulphur in this oil. I send some specimens with this letter.

This composition is evidently still running down the wall, though slowly, in many places. Being yet soft it cannot be fixed to the surface of the stone, as a body becoming solid in a short time may be expected to be; and it is very probable that a large portion of that which was applied to the surface has sunk inwards (for, under the summer’s sun its flow and absorption may be expected to be much quickened) into the mass of the stone. I removed some of the surface of the stone at the top or parapet part of these walls, but upon chemical examination could find no remains of the preparation in it. The stone seemed restored to the first or unprepared state; and at these places, and almost everywhere where the oil was not visible in runs upon the surface, water put upon it was absorbed as fast as upon the unprepared stone surfaces.

There is nothing in the appearance of the prepared stone which leads me to suppose that its surface has undergone any permanent protecting change; there is nothing by which I can perceive that any protecting or extraneous substance has been permanently fixed in the surface of the stone; nor is there anything in the description of the substance, or in the nature of the portions still found here and there, where, by reason of its fluidity it has accumulated, that leads me to expect the process can confer permanent protection upon the walls.

I have, &c. | (signed) M. Faraday