This was a strong move of God which brought 400 (a quarter of the island) to the Lord. The revival touched all the churches and there was great unity on the island, which was in contrast to the division that had been experienced in previous years. Several islands were affected by the revival.
For a more detailed account see, 'Glory in the Glen,' by Tom Lennie, published by Christian Focus Publications, p84-8.
I think the building marked is the Baptist Chapel.