William Pigott to Faraday   19 November 1862

T House Nov 19 / 62

My dear Faraday

Ere we enter on the task of trying to keep oil merchants purest - or rather that they should give us a pure colza oil - I wish you could suggest any test as to the specific gravity per gallon or any other that may occur to you[.]

I hear the Liverpool authorities have their oil analyzed as to the proportion of mucus in it by which I learn the tendency to clear more or less is ascertained - but all these points are nonsense when submitted to you as your knowledge will lead you to many valuable tests if any exist - at any rate I know I am right in thus drawing your attention to the subject - and with a hope you are well believe me ever

Yours faithfully | William Pigott