Faraday to John Barrow   13 April 1837

Royal Institution | 13 April 1837

Sir

I have made a very careful examination of the copper bolts¹ which you sent to me and cannot find any thing in the metal which will explain what is I presume a great and rapid decay. There is a trace of lead, a trace of iron, and the smallest trace of zinc in the copper but the quantities are far too small to account for the result[.]

Whether as accidental association of the bolts with other substances than the wood and water by which I presume they have been surrounded, has occasioned any voltaic action by which the injury has been caused is more than I can say, though not unlikely for being ignorant of the circumstances I have nothing to guide me in that respect. The crust upon the bolts is essentially the protoxide of copper and not a carbonate or a sub chloride but this result which in conjunction with others might have been useful gives but little information by itself[.]

I have put the bolts in relation to other copper of good quality but I do not find that they give any voltaic results which would lead to the conclusion that they are more corrodible than such good copper[.]

I am Sir | Your Very Obedient Humble Servant | M. Faraday

Sir John Barrow | &c &c &c