Faraday to Jonathan Frederick Pollock   19 March 1824

Royal Institution | Albemarle Street | Friday March 19th

My dear Sir

I am afraid I shall give you but a bad account of the gases for I have but a few moments to spare. I think I sent you a copy of the paper at least I hope so for I have none left[.] However you will have it in the Transactions[.]¹

Nine gases gave way before the attempts I made to condense them these are - Sulphurous acid - Sulphuretted hydrogen - Carbonic acid - Euchlorine - Nitrous oxide - Cyanogen - Ammonia - Muriatic acid - Chlorine

²

Your question with regard to carbonic acid is answered above[.] Of course the pressure of all these bodies increases with any increase of temperature and in consequence of the expansive power of some of them I have had several explosions & some wounds[.]

I perceive you wish to know the greatest pressure I have used. The nitrous oxide as you will perceive requires a pressure of 50 atmospheres at 45° and during the process by which it is liberated which consists in heating a closed tube containing nitrate of ammonia up to 300° of 350°F. The pressure within cannot have been less I think at times than 100 atmospheres probably much more[.]

I fancy I perceive a hint in your note at a vapour or gas engine - but of this we will say nothing[.] If such a thing is made (and there is no want of power) you shall know of it immediately: be assured that all proper attention is given to this point but as it is wiser not to talk of expected results³, than to talk & fail we will in this not imitate our friend of Fleet Street⁴.

I was amused the other day at the House of Commons (in a Committee) by your Brother - Not long since I was called upon for an opinion in a Committee on the comparative advantages of oil & coal gas[.] Mr David Pollock⁵ strongly examined me against oil gas. A day or two ago a bill of a similar kind for another place was before a committee and he had to be just as anxious for oil gas as he had before been for coal gas⁶. I know that this is nothing to you but it is most amusing to me.

Ever Dear Sir | Yours Very Truly | M. Faraday

Fredk Pollock Esq | & & &

Address: Frederick Pollock Esq