Hydrometer

I have a hydrometer i got from the chemical supply store, so in a recent post where i said i don't have a hydrometer... i must confess, i DO have one, but i have no idea how to take a reading from it. This hydrometer looks different from yours; it is a set of 3, plus a thermometer.
The three hydrometer things have a scale 0 to 40, 40 to 70, and 70 to 100. They all have a scale of 10 points til the next number. Having read you guys mention gravity readings in nearly every thread, i had an idea of what to look for or what the reading will look like.
I tested the 0-40 one in plain water (at 20 degrees C), and it was exactly 0. So i thought yay, now i can take readings of my must and see what numbers i get. I was fully expecting to get something 0.9 to 1.09 or something like that... anything ABOVE zero. But every reading i took of anything but water ended up with something in the area below the zero, which has no scale.
So, being clever as i am, i used permanent marker and drew a scale down to 10 points below the zero. So what did i get? Most of the time, a reading would end up even lower than the scale i had drawn. And the must? Take plain apple juice for example. Shouldn't be anything out of the ordinary where it would have an incredibly high or incredibly low gravity...

Any ideas how i am supposed to read this, or how i can improvise?

If I didn't know any better, it sounds as if what you have are hydrometers that read in a scale other than Specific Gravity (density ratio relative to that of water). Two examples would be Brix or Oechsle. My suspicion is that they are Oechsle, which is principally used in making German wines.

keep in mind that SG = the density of your liquid divided by the density of water. You could always do this.

Take a hydrometer reading of any common liquid, other than water, oil or something like that. Then look up that liquid's density, and divide by water's density. This will give you a specific gravity to coordinate with whatever hydrometer reading you got with your first test. This will then allow your to calibrate the rest of the marking on your hydrometer. Hope that helps, man that felt like an old engineering lab haha

It recently ocurred to me that there is another likely candidate for your hydrometers - those that use the Baumé scale. I just saw a set of 3 that have the following ranges 0-35, 35-70, & 70-100 °Baumé.

Still there are some things that bother me about your hydrometers:
1) The unknowm scale. There should be some indication of the hydrometer's scale units somewhere on the scale itself, or in the literature that should have come with them.
2) Hydrometer readings are temperature sensitive, and therfore require corrections. The reference temperature (°F or °C) should be specified on the hydrometer's scale.
3) There are several types of hydrometers and not all of them are designed to measure sugar solutons.

You noted you bought these hydrometers from a chemical supply store. I'd start with them and ask for these details. Do they have a website?

I like Wikipedia: Baumé scale - Wikipedia, the free encyclopedia
The set i have does have a little booklet with a couple charts in it. I do know that it says to take the reading at 20 C.
The chem supply doesn't have a website. Its just a little shop.
On the chart in the booklet, there are some numbers i recognize, like 0=0.998 and such... but thats all starting at zero and going up (and as the 1-100 number goes up, the number 0.998 comes down, until finally 100=0.789). I think the 1-100 is a percent scale (percent of what, I don't know, maybe percent of water?).
Ok thats encouraging in that it seems there is a way to use this hydrometer... but then, all of the non-water liquids i have tried end up somewhere in the region below zero. So, what, do i just guesstimate that its 1.046 or something? With the additional 'below zero' scale i drew on it, i could fairly accurately guesstimate (-1)=1.0 or 1.02.

EDIT: What is a normal OG for apfelwein, simple cyser, and mead? Would 1.02 be a crazy OG? What should a simple cyser finish at? I'll do some experimenting to figure this out. It would be easier if we knew for sure what this scale is, and what the chart is. The annotations in the booklet are Chinese. I can read Chinese, but this is scientific. I mean even in English, most citizens don't know what Specific Gravity is...

There's still too much uncertainty in the information you're providing. Do you have a gram scale - preferrably a digital scale?

If so, perform this test. Weight out 10g of pure table sugar. Next, weight out 90g of pure water. Mix the two until all the sugar dissolves. Cool the sugar solution to 20°C.

Now use your lowest range hydrometer to measure the solution. If that hydrometer does not read on the scale, try then next range, and so on.

What you made is a 10° Brix sugar solution, whose SG is 1.040. If none of those numbers are somehow displayed on the hydrometer, then I would think your set is not designed to measure sugar solutions.

If you need more test solution volume to use the hydrometer, use 100g sugar and 900g of water.