Slocum received a pleasant surprise after he landed in Apia. What was the surprise?

Slocum arrived in Apia and was greeted there with great warmth. There was a great surprise in store for Slocum - a visit by Mrs. Robert Louis Stevenson. Slocum was also invited to go to Vailima, the Stevenson home. Slocum discusses how the visit and invitation were particularly enjoyable after Slocum's sojourn into Robinson Crusoe's realm.