Isambard Kingdom Brunel to Faraday   18 June 1847

18 Duke St. Westr | 18 June 1847.

My dear Faraday,

I feel great compunction in writing to trouble you with inquiries but good nature is always abused and therefore you cannot hope to escape. If the naphtha or ammonia will not prejudice the creosote¹ why is coal tar decidedly destructive? - of which there is no doubt in my mind - from numerous results is it merely its mechanical defects of viscidity and not penetrating and yet forming an injurious coating - in my ignorance I had fancied that the ammonia was injurious.

I am &c | I.K. Brunel

M. Faraday Esqre