Experiments and measurements...**vs** assumptions and eyeballs. I DO have issues getting consistent decimal points, but here's some conclusions from rough draft notes.

'**MV**' used for simplicity, since pure H_{2}O has miniscule density variations at temp.

If we go with the reference '1' for density, then grams, milliliters, cm^{3} (cc), etc all will have the same 'number'. I just don't fool with showing the conversion to 'inches'...

4"cylinder, 1" deep, 4°C (39.2°F) pure H2O = 205.96MV

volume=**H**×**π**× **R**^{2} = 1 × 3.14 × 4 = 12.57 cu.in. = 205.93 cc = 205.93ml = 205.93 gm (205.93MV)

NOTE: An 8x1 cylinder MV should be EXACTLY 4 times the MV of a 4x1 cylinder. The radius of the 4” is doubled, so **H**×**π**×(**R2**)^{2} .

Does** 201gm = 1”, **or does **206gm = 1”? **The answer can be** YES **for both queries... heh... .

**‘M**ass/**V**olume’.

IF I ‘weigh’ my liquid, I MUST FOLLOW THE MATH for ‘cylinders’, and the density of water, related **exactly **to the size of the collection vessel. 800gm from an 8” collector is NOT the same as 800gm in a 4” collector! However *800gm in an 8” IS the same as 200gm in a 4”*.* Assuming the dimensions are in fact accurate at the cylinder mouth*.

QUERY: Variations in observations must be related to exact size of 'collecting' cylinders? And/or calibration of visual indicator 'magnifying' cylinders?

**Collecting:** STRATUS

Now,** One** of my Stratus (4”) cap inner diameter was so low, I simply didn’t trust the caliper inside measurement (averages), 3.952±.... so to convince myself,

I made a wax cast of the lip... **attachment 1**. Yep, that’s significant because if I assumed it was 4 inch gauge, I’d be incorrect. This 3.952 cylinder can only MV 200.96 / inch! IF the inner cylinder it feeds indicates 1” that will be fine. As long as I keep the cap and cylinder as a ‘set’.

BUT my Stratus **inner** cylinders are all over the place at 1” MV:

**(a)**200 **(b)**201 **(c)**202 **(d)**198 So with THIS ‘Stratus Sm’ cap, the selected inner cylinders would variously:

**(a)**over-report , **(b)**accurate, **(c) **under-report, **(d)**over-report!

And if I use my 3.981± Stratus cap with ANY of those 4 inner cyls, at 1”it will drop 203.97MV, and... **all 4 inner cylinders, would over-report**visually!

Furthermore, if I was reporting using 'weight' method, AND if I were using 201gm/inch, I'd 'over-report', and if I were using '206gm/inch' I'd Under-Report!

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**Assuming my 4” outer cylinder is 4”, and my digital scale says 205.96 gm, I have an inch of precip. No problem.**

BUT 1” of rain = 205.93 (206) gm in a 3.956 cylinder is NOT valid.

ALL MY stratus outer cylinders are virtually (averaging) 3.956±. BUT ONE INCH ain’t 206gm!

*h × π × r*^{2} = 1 *×* 3.14 *×* (1.678)²= **201.42MV** ...

*SO DOCUMENTS WHICH STATE “201gm” in Stratus outer cylinder would be correct,±. Using 206 would be incorrect for the Stratus!*

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TROPO

I've 2 Tropos, one is production series, one is a field test version (differences are mostly cosmetic, dimensions are identical) BOTH the CAPS, INNER CYLINDERS, and OUTER cylinder dimensions match exactly between the 2 versions.

**206gm would be correct for a TROPO cap!** (*Actually, 205 might be a tad more accurate based on my measurements*)

Those 'caps' are ±3.988± avg around the rim.

..the math says that a 3.99” diameter cylinder, one inch in depth, with water at 4°C or 39.2°F with a density of 1, will MV 204.9.

(Result depends on how you round the numbers)

For this, within miniscule decimals, the caps are identical... and other ‘constants’ are... ...constant..

In fact, BOTH my Tropos indicate 1 inch right at 205± MV.