One hymn which my Grandfather Idris would sing is "Tell It Again." It was also known as the "Gypsy boy" song which might not be entirely politically correct in today's world but that is what it was called.
The song was written by Mary Bridges Canedy Slade, the wife of a Pastor. She also wrote numerous others. These songs, as with so many old hymns, were often inspired by an experience of the composer or one which they had heard about.
Mary always said the song was based on a true story. A missionary in England walked into a gypsy camp to visit a dying boy. The minister recited the famous verse John 3:16 to him. "For God so loved the world He gave his only begotten son, that whosoever believed in Him should not perish but have everlasting life." The boy responded faintly, "Nobody ever told me."
Heart wrenching stuff for a Christian to hear and I can only imagine how it stirred the heart of a missionary, church elder and preacher like my Grandfather Idris Davies. He may have heard it first in the revival meetings he used to attend as my Great Grandfather Price Davies preached. Below is the sheet music which contains the brief annotation of this story at the bottom.
Fittingly the first stanza is: "Into a tent where a gypsy boy lay, dying alone at the close of the day, news of salvation we carried: said he: "Nobody ever has told it to me."
 The following website was very helpful in discovering the history of this song: http://wordwisehymns.com/2010/01/18/today-in-1826-mary-slade-born/