选用图1所示的玻璃管，配一抽气机，先在容器A中装入一种已知密度为pA的液体，容器B中装入待测液体，在图中C处接抽气机抽出少量气体，结果使A容器的液面上升hA的高度，产生了大小为pA的液体压强，且PA＋PC=P0．同理可得：PB＋PC=P0，从而得：PA＝PB，即：PA·g·hA=PB·g·hB The glass tube shown in Fig. 1 was selected and an air pump was used. A liquid with a known density of pA was loaded in the container A. The container B was filled with the liquid to be measured. The air pump was connected at the position C in the figure. A small amount of gas was withdrawn, resulting in the liquid level of the A container rising by the height of hA, resulting in a liquid pressure of size pA, and PA+PC=P0. Similarly, it can be obtained: PB+PC=P0, so that: PA=PB, namely: PA·g·hA=PB·g·hB