Assessment of these two methods

I think that it is right to put these into context. The properties treatment would have been time consuming to use as I have said but all the quantities involved are readily understood. The Mach number treatment that leads to one set of ratios of properties for all reversible, adiabatic one-dimensional expansions permits the construction of tables with Mach number as the independent variable. This table would have reduced the calculating time significantly. But the digital computer has reversed this position. It is now easier to use the earlier method of direct use of properties.