John Harper was an evangelist who had great success. He was doing so well that this church was built for him, which sat 550. The church was in almost continual revival. In 1905 over 1,000 were converted and the church had to be extended.
For more information see, ‘Glory in the Glen,’ by Tom Lennie published by Christian Focus Publications, p102-3.
The map can be seen online at the National Library of Scotland Website.