Now he seized her hand, and drawing her arm through his, led her quickly backwards and forwards, talking fast and earnestly.

It would not do to hesitate, for by a moment's appearance of uncertainty all would be lost.
"No; of course you cannot understand the vast importance of this discovery.

I must explain.

I must enter into historic details, and I am so much overcome by this extraordinary turn of fortune that I can hardly speak.

Remove all doubt from your mind, my dear lady, for we have already triumphed.