smooth plots using dot matrix printers or x y plotters such plots may include for example cumulative mass percent finer or coarser vs diameter cumulative area percent finer or coarser vs diameter cumulative number percent finer or coarser vs diameter and analogous histograms processed data can also be presented in tabular form it will be understood that repeat analyses or analyses of new samples using the same suspending liquid do not require complete repetition of the foregoing operations for example introducing a new sample into the same liquid does not require recalibration of the i o values for the cell but does require reestablishing the i 100 values therefore the cell can be rinsed drained and loaded with the new sample according to appropriate steps of fig1 and 14 new sample data entered the new run preprogrammed per fig1 and new i 100 values obtained according to fig1 then the analysis can proceed as described above operation of the x ray safety interlock will be apparent from the above description of its components whenever the cell compartment door 130 is opened the cam 146 allows the plunger 144 and rocker member 136 to move toward the door raising the horizontal member 138 to a position over the slit 41 only when the door 130 is again completely shut will x rays be permitted to enter the cell compartment fig2 and 21 show an alternate embodiment 315 for the construction of the sample cell the cell 315 is modified at the location at which the passageway 118 as shown in fig5 enters the.