He had in 1827 declined the appointment of Professor of Chemistry in the University (afterwards called University College) of London, giving as his reason the interests of the Royal Institution. He wrote:—
I think it a matter of duty and gratitude on my part to do what I can for the good of the Royal Institution in the present attempt to establish it firmly. The Institution has been a source of knowledge and pleasure to me for the last fourteen years; and though it does not pay me in salary what I now strive to do for it, yet I possess the kind feelings and goodwill of its authorities and members, and all the privileges it can grant or I require; and, moreover, I remember the protection it has afforded me during the past years of my scientific life. These circumstances, with the thorough conviction that it is a useful and valuable establishment, and the strong hopes that exertions will be followed with success, have decided me in giving at least two years more to it, in the belief that after that time it will proceed well, into whatever hands it may pass.
In 1829, however, he was asked to become lecturer on chemistry at the Royal Academy at Woolwich. As this involved only twenty lectures a year he agreed, the salary being fixed at £200 a year. These lectures were continued until 1849.
TRINITY HOUSE APPOINTMENT.
In 1836 the whole course of his scientific work was changed by his appointment as scientific adviser to Trinity House, the body which has official charge of the lighthouse service in Great Britain. To the Deputy-master he wrote:—
I consider your letter to me as a great compliment, and should view the appointment at the Trinity House, which you propose, in the same light; but I may not accept even honours without due consideration.
In the first place, my time is of great value to me; and if the appointment you speak of involved anything like periodical routine attendances, I do not think I could accept it. But if it meant that in consultation, in the examination of proposed plans and experiments, in trials, etc., made as my convenience would allow, and with an honest sense of a duty to be performed, then I think it would consist with my present engagements. You have left the title and the sum in pencil. These I look at mainly as regards the character of the appointment; you will believe me to be sincere in this when you remember my indifference to your proposition as a matter of interest, though not as a matter of kindness.
In consequence of the goodwill and confidence of all around me, I can at any moment convert my time into money, but I do not require more of the latter than is sufficient for necessary purposes. The sum, therefore, of £200 is quite enough in itself, but not if it is to be the indicator of the character of the appointment; but I think you do not view it so, and that you and I understand each other in that respect; and your letter confirms me in that opinion. The position which I presume you would wish me to hold is analogous to that of a standing counsel.
As to the title, it might be what you pleased almost. Chemical adviser is too narrow, for you would find me venturing into parts of the philosophy of light not chemical. Scientific adviser you may think too broad (or in me too presumptuous); and so it would be, if by it was understood all science.
He held the post of scientific adviser for nearly thirty years. The records of his work are to be found in nineteen large portfolios full of manuscripts, all indexed with that minute and scrupulous attention to order and method which characterised all his work.