Faraday to Robert Faraday   10 December 1842

Royal Institution | 10 Decr. 1842.

My dear Brother

The invention may be called a means of ventilating oil and gas lamps for the purpose of carrying away the water, carbonic acid, and other products of their combustion in a more advantageous manner than has hitherto been done¹. It applies to Argand burners, i.e. those with glass or such like chimnies, and consists simply in dipping the end of the pipe which is to serve as a ventilating flue, more or less into the glass chimney. Thus if an oil or gas Argand lamp have a burner of 7/8 of an inch in diameter, and a lamp glass on it of the usual proportions, I find that a tube also 7/8 of an inch in diameter, more or less, according to its length and other circumstances, will carry off all the results of the combustion of such a lamp, the lower end of the tube being inserted into the top of the lamp glass and the upper end carried into a chimney, the open air, or any place where it may be considered convenient to dispose of the burnt air and fuel. The lower end is best placed centrically in the lamp glass; but the degree of its insertion may be more or less at pleasure[.] In a quiet place, even when almost at the top of the glass it is sufficient; in other cases an inch or more of insertion may be needed. In some of my experiments I have made the burner end of the ventilating tube a little funnel shaped; still however keeping it within the lamp glass, as in the figure:-

and in experiments with oil lamps, I have introduced a throttle valve into the ventilating tube to govern its draught that the latter might be regulated so as to be strong enough to draw up and carry off all the results of the combustion and yet not so strong as to increase the draught of air by the flame; for when that occurs it causes a quicker charring of the cotton than usual, an effect it may be desirable more or less to avoid.

And now Dear Brother, believing this particular arrangement of the ventilating flue to be my own invention, and having no intention of turning it to any pecuniary use for myself, I am most happy to give freely all my rights in it over to you, or any body you may name for your good²; and as Mr. Carpmael³ says we may legally and equitably make this transfer of rights in this way, I write you this letter describing the principle and arrangement of the invention as far as I have carried it. Hoping it may be productive of some good to you, and of no harm or trouble.

I am My dear Robert | Your Affectionate Brother | M. Faraday

Address: Mr. Robt Faraday | Post Restante | à Calais | France