The Box Tunnel had been the subject of much criticism before the works were commenced; and during its actual construction it did not escape the unfavourable notice of those who were ignorant of the difficulties which presented themselves, and the means which had been taken to overcome them. Indeed, for some time after the opening of the line, there were travellers who used to avoid the terrors of the tunnel by posting along the turnpike road in that part of their journey. Mr. Brunel never troubled himself about the ordinary gossip which is always circulated concerning any remarkable work; but matters assumed a different aspect when, a year after the completion of the tunnel, doubts were expressed as to its safety by an eminent geologist, at a meeting of the Institution of Civil Engineers. Mr. Brunel, who was on terms of friendly intercourse with the speaker, addressed to him the following letter:-- June 21, 1842. I assure you, my dear Sir, that when my attention had been drawn to the statements reported to have been made by you on this subject, I refrained as far as possible from expressing any opinion. I thought it my duty to read the notes taken, but I never said that I thought your statements were correct. Indeed, I had hoped to have avoided the necessity of making any observations upon these statements; but as a letter to Mr. Saunders on such a subject is almost the same thing as if it were addressed to myself, and as it was shown to me, it would not be candid towards you if I now refrained from saying, that the opinions you are reported to have expressed with respect to the Box Tunnel are by no means considered correct, either by myself or by those others who, from being intimately acquainted with the rock as it was really found, and the works as they were really executed, are capable of judging.