WHAT IS "DISPLACEMENT PUMPING"?
This is not a new way to pump, but it is an effective way to measure the performance of your system and technique. You can quickly find out what your actual gain is and how long it takes to get it. No special equipment is needed and it's not complicated to do.

Displacement means to dis-place, or take the space occupied by something else. In pumping, as your package grows, it takes space previously occupied either by air or water in your cylinder. If you want to know just how much growth you are achieving, a tape measure is not a very accurate means of finding out- but displacement of water is very precise.

By pumping wet and measuring the level of water in the cylinder in a consistent method, you can tell exactly how much your body volume has changed. By timing your pump session and recording your vac level and time, you can also find out exactly what conditions create the fastest gain for you. This is particularly valuable if you are working on a growth program, but often of interest to any pumper.

HOW DO YOU DO IT?
The tool needed here is a way to measure the change in water level inside the cylinder. To measure the change in YOU, all of your body parts must be under the water level in the cylinder. Any part in an airspace when the measurement is read will not be measured! There are two ways to consider the measurement. The best is in a metric scale in Milliliters (Ml) or Cubic Centimeters (CC's) , which will result in precise volume readings. The second is in vertical inches, which will mostly show relative growth, but can be converted to Cubic Inches as well. You need a cylinder with enough space so that you will not run out of airspace above the water as you grow, and preferably with parallel sides through the center.

An ASTJ or glass STJ will do fine. Follow these steps:

PART ONE:

1. Put a strip of tape that you can write on lengthwise on the tube, end to end.
   
   
2. Add water to the cylinder, then put it on your body and use a light vacuum to keep it sealed. Next, lie down in a position where the cylinder is vertical with the entry down. IF the water does not cover you completely, add more until it does.
   
   
3. Put a mark on the tape exactly at the water level. This will be your "Zero" point.
   
   
4. Remove the cylinder, trying not to lose any water. Now with the cylinder vertical and entry up, put a second mark on the tape at the current waterline, preferably with a different color pen. This will be your "Fill" point.

From here on, the process changes depending on whether you want to measure in volume of displacement or in inches of water.

PART TWO, Volume of displacement:

1. You are going to create a scale which shows the number of Ml or CC's of water from the zero point going towards the bottom of the cylinder. You will need a kitchen or laboratory measuring cup with a metric scale, listing Ml (easiest to find) or CC's. Put the cylinder upright on a countertop and add water to the "Fill" point.
   
   
2. Add a second piece of tape right next to the first, that starts below the fill point and extends to the top. Mark the fill point on it by transferring it from the original tape.
   
   
3. Using the measuring cup, add 100 Ml of water to the cylinder. In a 3-qt. STJ, the level will rise about 3/16". Put a fine straight mark at that level, on the second tape.
   
   
4. Repeat that step 10 times, and you will have a scale for 1000 Ml, which is one liter, or slightly more than a quart of water. You can continue the scale as far you wish on the parallel section of your cylinder.
   
   
5. Remove the second tape, and turn it around- (top to bottom) lining up the transferred "fill" point with the "Zero" point on the first tape. Transfer the "Fill" point from the first to the second tape.
   
   
6. Remove the first tape, it is no longer needed.
   
   
7. You will now have a scale that will measure the level of water in the inverted pumping position.

As you pump, the water will rise on that scale from the zero point when starting to reflect whatever actual displacement volume change occurs in your package.

PART THREE, Inches of water: (note two methods)

1. Method one: Using a common ruler, place the zero of the rule at the Zero point on the first tape, and transfer the markings from the rule to the tape. You are measuring from Zero toward the BOTTOM of the cylinder.
   
   
2. Method two: Glue or tape a short ruler to the cylinder in the same fashion.

As you pump, you can measure the raise in water level in fractions of an inch as you grow. This shows when you are growing, and how much compared to other sessions.

If you are handy with math, these numbers can be converted to actual displacement figures as well. To do that, calculate the cross section area of your cylinder with this formula:

(R2XPi) Or- "Radius squared x 3.14= area in square inches". This will also be the cubic inches of displacement per inch of cylinder length. For instance, a 4" cylinder has a radius of 2"; 2 times 2 equals 4, times 3.14 equals 12.56 cubic inches per inch. Thus if your pump session raises the water level 3 inches, (12.56 X 3) you will have enlarged by a total displacement of 37.68 cubic inches.

TO USE THE SYSTEM:

• Start by filling the cylinder to the "Fill" point before use.
  
  
• Begin a light pump, and go to the "reading" position- the cylinder inverted and straight up, all body parts below the water level.
  
  
• Read the water level and note it. Due to the natural changes in size at different times, your initial level may be slightly above or below the zero.
  
  
• Check the level from time to time as the pump progresses to find out just how much actual change is developing.

Now, start thinking in Cubic Centimeters or Cubic Inches instead of inches of circumference or length!