Lucy Joan Howard de Walden¹ to Faraday   22 July 1864

I ask for no remarks but if I have left any point untouched you care to hear of, my direction is British Legation - Brussels

Hotel Matthew | Paris | July 22 1864

Dear Dr Faraday

I am sure you will neither think it impertinent nor indiscreet of me to write a few lines to you telling you of my Magneto Electric experiences since I had the pleasure of seeing you² - for I ask for no remarks.

The Machine you saw in Gravel Lane³ was fitted with the Pigmy⁴, & supplied with our Lamp cut down, put into an ordinary ship’s lantern, that is, the lens was of the ordinary thickness & quality - i.e as uneven as possible & 3 inches thick. Very much against our opinion - but our R.N. associate declared nothing else could answer at sea. There was also a serrin⁵ Régulateur he had been using with the Lime Light - with which Captain Bolton⁶ & Captain Colomb⁷ had been telegraphing from the back of the Isle of Wight to Portsmouth.

We had some difficulty in continuing operations - the Machine used at the back of the Isle of Wight was the same shewn at Blackwall in 1859 with an improved commutator. The Light placed in front of a mirror - The Pigmy could read the Signals made by this light with ease at 30 miles distance they then considered it “pleasantest to read” - but after the Pigmy had sailed away 28 miles, we could only read her signals, with such difficulty, that we recalled her when she was 30 miles off - convinced that it was idle to work with such a lantern. After that work was over, we on the following night, signalled to Portsmouth, the night was hazy, & the 1st answer we got, was, “What has been the matter all the week - your Light is beautiful what is it.” They had signalled to Portsmouth with the Lime Light before.

I went to Havre - having obtained an order from the French Gov: to shew me all the Lighthouses, & answer every question - & shew me every detail. I drove up to Cap la Hève which is I think nearly 400 feet above the level of the Sea & examined both oil & M. Electric apparatus. The two towers are of the same height on the same plain about - I roughly guess, - 150 yards or 200 apart - low square towers with a broad balustrade - ([word illegible] the water room) 5 or 6 feet below the floor of the oil apparatus & level with that of the Electric Light - (where the alteration was being made a large number of lamps with Reflectors was placed on the wall inside the balustrade to replace the removed dioptric) on the N.E. corner of the wall a projection is made stone whitewashed in the centre & a Lantern above & below, of the height of the Lens, & just 3 or 4 inches between the glass of the Lens & that of the Lantern - divided into 4 bent panes fitting into one another -

The two Magneto Electric Machines are below, worked by two Steam Engines with straps - the St. Engines work sometimes alternate nights sometimes alternate weeks - when the Light on the Pier can be seen, one machine only, is worked, when the fog covers it, both; but the Steam Engine only is used. The St. E. makes 110 to 120 strokes a minute - from 3½ to 5 atmospheres pressure. When I was there, to work one machine it was nearly 4 - & over 5 for both the machines making from 360 to 400 turns per minute. With one machine at work, the Light was weak & very unsteady - frequently extinguishing itself - & not quite white. I could look at it without discomfort - when both were worked the Light became good - whiter, larger, & steadier - The Lens was made by Sautter - More accurate than the 3 first furnished by Chance, to Dungeness less so, than his last - with a contrivance at the back to shew the Lightkeepers if the focus is accurate - which stands in the way of a reflector.

I then went to Sea in a pilot boat - it being agreed that till 11 but one machine should work. After the second should be added to shew the effect. Till 11 the Light was very unsteady wavering - flickering weak & often extinguishing - I think I counted 7 times when it was quite out, before 11 - I was within 3 miles of the Lighthouses & but for the distinction of color could hardly have preferred it to the oil - At 11 the Light at once became larger brighter whiter steadier - very inferior to Dungeness in the opinion of the only man of the crew who knew Dungeness - & in mine too it still flickered & extinguished itself I think twice in the half hour - when the 2d was taken off, the Light was better than it had been previous to 11 & as we sailed further away the superiority of the Electric over the Oil became more apparent - & as the haze increased - but on our return at 3 AM. the fog grew thick the oil light became invisible & five minutes after the Electric entirely disappeared a mile off we could see neither - The Light on the pier was never covered -

I consider one machine of 40 magnets clearly unequal to the work. I impute the faintness at times of the Light - to the diminished speed - that when fresh coals are put on the revolutions fall below 400 - & the current is then too weak - the want of the commutator causes the great flickering & wavy appearance[.] The pilots & sea captains are memorializing the Chambers of Commerce to place the Light universally - I dare not lengthen my letter but must beg you to believe me V faithfully L. Howard de Walden

Address: Dr Faraday | Albemarle Street | W. | London