The following glossary of medical terms was assembled as part of a project on medicine from 1760-1830 but it includes some terms from a wider period. I have drawn on several sources, including, with the permission of the author, Medical Terms used in the late 18th Century which appeared on a now obsolete web site written my Melanie McClusky. Information from Dr Johnson's Dictionary, first published in 1755, is shown in red.
Figure 2 is a simple cartoon showing three different types of aquifers: confined, unconfined, and perched. Recharge zones are typically at higher altitudes but can occur wherever water enters an aquifer, such as from rain, snowmelt, river and reservoir leakage, or from irrigation.
Typical aquifer cross-section. An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials (gravel, sand, or silt) from which groundwater can be extracted using a water well.here are two end members in the spectrum of types of aquifers; confined and unconfined (with semi-confined being in between). Unconfined aquifers are sometimes also called water table or phreatic aquifers, because their upper boundary is the water table or phreatic surface.