So this is what I have tried so far. I hope that unpolished diagram is able to be interpreted. Fortunately, the sensors only take 50 microamps to run, so even running 20 at once is something like a milliamp of power from the arduino. As it stands now, if I hook up a multimeter to my arduino ground, and another to the Vout pin, I get the sensor output plus 5 volts, be the output positive or negative voltage (both are working now).
This is an improvement, as all my output is now positive, but obviously the analog input pins support only up to 5 volts, and depending on the temp, the sensor is outputting between 4.45v and 6.5v. For exampe, at room temperature 22C, I read 5.22 volts. trouble is, the arduino reads up to 5v, so I need a way to read about 3/4 of the output voltage. In order to do that, I attempted to create a voltage divider which would do this. It seems to me like this should work, but I'm getting unpredictable results. For instance, at 5.22v I should be getting 3.912 volts, but I may be reading 3.7v or something.
It seems like the voltage should be divided by the ratio of the voltage divider circuit. I have set this circuit up on 3 breadboards with different resistors, and it isn't. Does anyone know why not, and what could be done to fix it?