This is actually three spells : Day-spirit's Blessing, Dusk-spirit's Blessing, Night-spirit's Blessing. The Cleric must learn each separately.
Using this ritual the Cleric makes contact with a Great Spirit of a region, allowing the Spirit to use him as a conduit. The Blessing extends to those around the Cleric, protecting them from the hardships of the Great Spirit's chosen environment. The Cleric, and a number of other people up to the Cleric's Level, gain +5 Survival for 1 day. The Day-Spirit's Blessing gives Survival / Drylands, the Dusk-Spirit gives Survival / Twilight and the Night-Spirit gives Survival / Nightlands. The effect of allowing such a mighty Spirit into his body affects the Cleric badly. At the end of the day he takes a Spirit Wound (Ridden).
It is possible to dilute the Spirit's Blessing amongst a larger number of people. The Cleric can give Survival as follows :