Truly portable steam engines were first practically available in the period after 1850.  An early application was in the "fire engines" which were characteristically vertical boilers providing the steam power to a water pump.  Portable steam engines of various sizes were available to supply power to industry and for the first time to agriculture where frequency of operation and open air operations precluded the practical application of stationary steam power.  The first steam engines produced by the Firm that eventually became known as  Sawwyer & Massey, were portable engines pattented by L.D. Sawyer of Hamilton circa 1870.