Jones, who moved from the United States to Carmarthen in 1897 in order to head the congregation at Penuel, the chapel is said to have witnessed many supernatural "manifestations" and instances of "divine healing".

Miracles and supernatural manifestations were reported as having been regularly witnessed by the congregation at the chapel, so much so that by 1904 it was "common knowledge that they regarded medicine and surgery with contempt" in favour of mysticism and faith healing.

Jones would have been "transformed" by his two "baptism of power" experiences, with Marcel noting that, historically, those who had experienced such "went from being an ordinary preacher to an extraordinary one".

The organ is in a recess on one of the galleries and underneath this there is a free classical arcaded pulpit behind which is a curved and panelled back with pediments.

[2] At the time of its renovation in 1910 it was stated that the chapel could accommodate 800 people and was designed in such a way that the occupiers of any pew on the ground and gallery floors have a full view of the pulpit and organ.