nH2O 1.4.2 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The most popular version among nH2O for Mac users is 1.4. This free Mac application was originally designed by nHance Technologies, Inc. We recommend checking the downloaded files with any free antivirus. The application belongs to Productivity Tools.
From the developer:
nH2O is a “water property” calculator that calculates various thermodynamic properties of steam and water. The app is based upon the Modular Modeling System (MMS) steam property library which is composed of a set of routines, some polynomials and some table interpolations of the thermodynamic properties of steam and water.
You may want to check out more Mac applications, such as Calculus, Metes and Bounds or Geometry, which might be similar to nH2O.