For the first time there was constructed with this machine [locomotive engine] a self-acting mechanism in which the interplay of forces took shape transparently enough to discern the connection between the heat generated and the motion produced. The great puzzle… — Carl Ludwig Copy Share Image
![“For the first time there was constructed with this machine [locomotive engine] a self-acting mechanism in which the interplay of forces took shape transparently enough to discern the connection between the heat generated and the motion produced. The great puzzle of the vital force was also…” quote by Carl Ludwig](https://sms4smile.com/quotes/img-quotes/5b7/carl-ludwig-102465_acting_for-the-first-time-there-was-constructed_2704200.jpg)