After walking up and down for about ten minutes he went back to the table and took up the letter.

The adhesive envelope opened easily, and Mr.Sheldon, by this ingenious stratagem, made himself master of his friend's business.
The "Alliance" letter was nothing more than a notice to the effect that the half-yearly premium for insuring the sum of three thousand pounds on the life of Thomas Halliday would be due on such a day, after which there would be twenty-one days' grace, at the end of which time the policy would become void, unless the premium had been duly paid.
Mr.Halliday's letters had been suffered to accumulate during the last fortnight.

The letters forwarded from Yorkshire had been detained some time, as they had been sent first to Hyley Farm, now in the possession of the new owner, and then to Barlingford, to the house of Georgy's mother, who had kept them upwards of a week, in daily expectation of her son-in-law's return.

It was only on the receipt of a letter from Georgy, containing the tidings of her husband's illness, that Mr.
Halliday's letters had been sent to London.

Thus it came about that the twenty-one days of grace were within four-and-twenty hours of expiring when Philip Sheldon opened his friend's letter.
"This is serious," muttered the dentist, as he stood deliberating with the open letter in his hand; "there are three thousand pounds depending on that man's power to write a check!" After a few minutes' reflection, he folded the letter and resealed it very carefully.
"It wouldn't do to press the matter upon him to-night," he thought; "I must wait till to-morrow morning, come what may.".