Share prices of top industrial gas, natural gas, and hydrogen company Air Products and Chemicals (APD -0.03%) just sank. Investors may have been spooked by some commentary from CEO Seifi Ghasemi, who had this dire warning on the last earnings call: I'd just like to caution everybody on the call that the economic situation in China is not as robust as people might think. As you know, we make products that are used instantaneously. We are a great leading indicator. And things are not really that exciting in t ...