This report presents abbreviations and fundamental conversion factors commonly used in manometry@ recommended definitions of pressure in terms of a column of mercury and water@ and for a large number of liquids@ tables of pressures indicated by@ or equivalent to@ heights of columns at various temperatures. These data have the object of facilitating and standardizing the use of manometers and U-tubes as direct pressure indicating instruments or in the calibration of pressure recorders and controllers. A discussion is included of the more frequent or more important sources of error in manometric measurements@ together with correction tables for mercury and water columns. To conform to general practice in this country@ English units of measurements are largely used (i.e.@ pounds@ inches@ etc.) and with several exceptions@ decimals are used to denote parts of units@ rather than octonary fractions. In particular@ it will be seen that conversion factors for kerosine@ gage oil@ alcohol@ dibromobenzene@ dibromoethane@ and acetylene tetrabromide are given only to obtain equivalent water columns at 60?? Further@ no conversion data are presented for benzol@ butyl collosolve@ carbitol@ nbutyl phthalate@ or halowax oil. The filling in of these omissions will have to await demonstrated need.