A liquid proportioning method using a chamber for a gas and a reception volume connectable thereto for a liquid with an aperture to the environment, wherein a desired volume is predetermined for the liquid to be taken up by the reception volume, a chamber negative pressure is determined which has to exist in the chamber to cause the desired liquid volume to be taken up in the reception volume after the aperture is dipped into the liquid and the chamber is connected to the reception volume, the chamber negative pressure is produced in the chamber, the reception volume dips its aperture into the liquid, and the chamber is connected to the reception volume and the desired volume of the liquid is taken up in the reception volume.