Secret of the River by Fred M. White — Read

The mere fact that Murray and Sidey were frequently absent in London on business had not prevented Nevil from striking up some sort of a friendship with Blanchin. It was to the latter's interest to encourage the old gentleman, but it was nearly the end of a week before Blanchin seemed inclined to fall in with the professor's hint that the latter might be permitted the favour of a visit to the laboratory.

This came about on the following Friday afternoon, not long before Murray and Sidey were expected home from town for the week-end. They were also expecting a visitor, Blanchin explained, who was coming down by car.