Alice have been looking forward to showing Ari the "new" Penny Arcade Lung Tester. It is made by National Spirometer Company of NY, NY, as early as 1899. Somehow, it has managed to survive all this time after these devices were made illegal to put in public places due to their role in the spread of Tuberculosis back in the early 20th century. The dial reads 0-100 ounces, which while not a unit of pressure, seems to correlate fairly well to "ounces per square inch." Note that while it is called a "spirometer," it actually measures pressure, rather than volume. So the obvious question - assum...

Alice have been looking forward to showing Ari the "new" Penny Arcade Lung Tester. It is made by National Spirometer Company of NY, NY, as early as 1899. Somehow, it has managed to survive all this time after these devices were made illegal to put in public places due to their role in the spread of Tuberculosis back in the early 20th century. The dial reads 0-100 ounces, which while not a unit of pressure, seems to correlate fairly well to "ounces per square inch." Note that while it is called a "spirometer," it actually measures pressure, rather than volume. So the obvious question - assuming it is in fully nominal working order - is how hard is it to blow a reading of 20 ounces (labelled "poor" on the dial), 35 ounces ("normal"), 45 ounces ("average"), or 60 ounces ("excellent")? And how do those numbers equate to PSI?