 laws (Duhem 1991 [1906], 82-83). Similar critiques are directed at Maxwell's and Lodge's different mechanical analogies of electromagnetic phenomena and at Kelvin's vortex atom model. Faced with failure of a model, they switch to new models that are inconsistent with other models they use. Such theories, Duhem concludes, cover only "a miniscule fragment of Physics" and the "fragmented representations may not be welded together to form a coherent and logical explication of the inanimate Universe" (Duhem 1903, 100). In a nutshell, then, physics developed according to the synthetic approach had failed, according to its critics. "Visualizable" material points or atoms subject to position-dependent central forces, so successful for representing celestial phenomena, were ill-suited to represent electromagnetic phenomena, "dissipative" phenomena in heat engines and chemical reactions, fluid phenomena, etc. Deformable bodies and viscous fluids are conceptually difficult to construct from atom-like material points; shearing forces are incompatible with central force assumptions; frictional and electrical forces are velocity-dependent. Physics had become a disorganized patchwork of poorly understood theories, each dealing with special cases in its own domain Michael Liston – Duhem: Images of Science, Historical Continuity, and the First Crisis in Physics 78 and inconsistent with others, without adequate unified foundations or empirically determined values of microscopic parameters. Lacking coherence, unity, and empirical determinacy, these theories could not claim to be explanatory or realistic. Analytic Treatments: Promises This is where the new physics of principles (Poincaré) or physics developed on the analytic approach (Duhem) comes to the rescue. Physicists responded to this crisis, Poincaré explains, not by giving up the dream that the universe is a machine, but by, in a sense, side-stepping the problems. Suppose we have a machine whose initial and final wheels are open to view but whose intermediate machinery 