I show and describe herein two forms of apparatus for obtaining such expansion and contraction and the required energy therefrom, and I also show two forms in which the energy so obtained is accumulated and stored. In connection therewith, I show the application of my invention to the running of clocks, but it will be understood that the invention is not limited in its application to that particular class of machine, and that it may be applied to any use of which it is susceptible. It is well known that all metals are capable of some degree of expansion and contraction, and some metals have this property in greater degree than others. The amount of expansion for each degree rise in temperature is quite regular, and is called the co-efficient of expansion. It is also well known that zinc has this property in greater degree than any other of the solid metals, its co-efficient of linear expansion being appreciably higher. For this reason, as well as because of its relatively low cost, I preferably make use of zinc in the construction of the expansible parts of my apparatus. One of the objects of my invention, therefore, is to provide an expansion device of novel construction and arrangement, which will generate energy and maintain motion during changes in temperature, to such an appreciable and useful amount, as to constitute it in fact a temperature motor. A further object of my invention is to provide means for accumulating or storing the energy thus generated. A further object is to provide means for applying the energy thus generated and stored. Other objects, such as compactness, durability and comparatively low cost of the apparatus, will appear in the following description, in which reference is had to the accompanying drawings. In the drawings:-- Fig. 1 is a front elevation, showing the application of my invention to a clock provided, in this case, with a mainspring as usual; Fig. 2 is a rear elevation of the same with a part removed; Fig. 3 is an enlarged perspective detail showing how the strips forming part of the expansion member or coil are connected up; Fig. 4 is a sectional view, on lines 5--5 of Fig. 1; Fig. 5 is an enlarged detail elevation, with parts removed; Fig. 6 is an enlarged detail cross section of the central portion of the apparatus, with part broken away; Fig. 7 is a rear elevation of the same with parts broken away; Fig. 8 is an enlarged detail of the upper portion of the apparatus shown in Fig. 4, with parts removed; Fig. 9 is a perspective detail, partly broken away; Fig. 10 is an enlarged detail of a portion of the ratchet mechanism shown in the lower portion of Figs. 6 and 7; Fig. 11 is an enlarged section of a flexible coupling shown in Fig. 7; Fig. 12 is an elevation of a modification of the expansion coil; Fig. 12ª is a perspective view showing how two of such modified expansion coils may be connected; [Illustration: _Fig. 1._ BANGERTER’S PERPETUAL TIME CLOCK]