_May 12_.--In moving No. 6, they left by some unaccountable neglect the top staves behind, and in that state two top polings were taken down. The ground being very bad, and high water at the same moment, the ground began swelling. Attention was called to several points, and Gravatt continued in No. 6. He drew out at the front of the top staves a shovel, and also a hammer, that had come through the ground above. They are the same which Isambard left at the bottom of the river, when he went down in the diving-bell. [Sidenote: Triumph of the shield.] _May 13_.--Notwithstanding every prudence on our part, a disaster may still occur. _May it not be when the arch is full of visitors!_ It is too awful to think of it. I have done my part by recommending to the directors to shut the Tunnel. My solicitude is not lessened for that: I have indeed no rest, and I may say have had none for many weeks. So far the shield has triumphed over immense obstacles, _and it will carry the Tunnel through_. During the preceding night the whole of the ground over our heads must have been in movement, and that too at high water. The shield must have therefore supported upwards of _six hundred tons_: it has walked for many weeks with that weight twice a day over its head. What flippancy and inconsistency in some individuals, who, without any knowledge of the subject, without so much as examining the state of the work, will without the least reflection and hesitation obtrude their suggestions upon every case. What shallow conceit for such to pretend they can know better than those that have already the experience that must result from years of deep thought, from days and nights of incessant attention; who have the advantage of the combined talents of several ingenious men, who devote their undivided study, the whole resource of their well-stored minds, to the enterprise; and to add to this, the benefit of the skill of one hundred miners and excavators. Among this class of men, some have been employed in the most perilous enterprises, when each individual must have acted upon his sole judgment, where, in fact, there is no room for an engineer to instruct and direct their efforts. How easy it is to attack everything, to detract from the merits of the best plan. There is always some weak point which may be open to the penetration of the shallowest mind. Then comes the exulting expression, _That I always said would never do, &c.,_ and all the consequences with it. [Sidenote: How easy to detract.]