How can an alcohol solution of CoCl2 be used to predict rain?

Question

Apparently, cobalt chloride is used in many weather-forecasting devices and I was wondering how an alcohol solution of it might be used to predict rain.

Answer 1

Create a barometer  using the alcohol and use the cobalt sat to color the solution.  This color makes it easier to see the solution which would otherwise be clear.

Take a tube sealed at one end.  Fill it with your solution.  closing the open end invert the tube and place it is a dish of  your solution.  Uncover the open end.  You now have a barometer.

If the level in the tube falls, the atmospheric pressure is lower and this indicates rain.