On this page of the guide to BioShock Infinite, you will find information about where to find infusions / essences in chapters 4 and 5. Information about each infusion features a description and a picture. You can obtain 3 infusions in chapters 4 and 5.
The Fraternal Order of the Raven - on the chapel's altar (where the sermon was taking place).
Lansdowne Residence - inside a chest found in the bedroom. The chest can only be opened by completing a side mission.
Gondola to Monument Island - on a lower level of the maintenance tower, inside a room located beneath the tower's archway.