[44] De Motu Animalium, I, prop. cciv, ed. 1685, p. 243.
[45] Harlé, On Atmospheric Pressure in past Geological Ages, Bull. Geol. Soc. Fr. XI, pp. 118–121; or Cosmos, p. 30, July 8, 1911.
[46] Introduction to Entomology, 1826, II, p. 190. K. and S., like many less learned authors, are fond of popular illustrations of the “wonders of Nature,” to the neglect of dynamical principles. They suggest, for instance, that if the white ant were as big as a man, its tunnels would be “magnificent cylinders of more than three hundred feet in diameter”; and that if a certain noisy Brazilian insect were as big as a man, its voice would be heard all the world over: “so that Stentor becomes a mute when compared with these insects!” It is an easy consequence of anthropomorphism, and hence a common characteristic of fairy-tales, to neglect the principle of dynamical, while dwelling on the aspect of geometrical, similarity.
[47] I.e. the available energy of muscle, in ft.-lbs. per lb. of muscle, is the same for all animals: a postulate which requires considerable qualification when we are comparing very different kinds of muscle, such as the insect’s and the mammal’s.
[48] Prop. clxxvii. Animalia minora et minus ponderosa majores saltus efficiunt respectu sui corporis, si caetera fuerint paria.
[49] See also (int. al.), John Bernoulli, de Motu Musculorum, Basil., 1694; Chabry, Mécanisme du Saut, J. de l’Anat. et de la Physiol. XIX, 1883; Sur la longueur des membres des animaux sauteurs, ibid. XXI, p. 356, 1885; Le Hello, De l’action des organes locomoteurs, etc., ibid. XXIX, p. 65–93, 1893, etc.
[50] Recherches sur la force absolue des muscles des Invertébrés, Bull. Acad. E. de Belgique (3), VI, VII, 1883–84; see also ibid. (2), XX, 1865, XXII, 1866; Ann. Mag. N. H. XVII, p. 139, 1866, XIX, p. 95, 1867. The subject was also well treated by Straus-Dürckheim, in his Considérations générales sur l’anatomie comparée des animaux articulés, 1828.
[51] The fact that the limb tends to swing in pendulum-time was first observed by the brothers Weber (Mechanik der menschl. Gehwerkzeuge, Göttingen, 1836). Some later writers have criticised the statement (e.g. Fischer, Die Kinematik des Beinschwingens etc., Abh. math. phys. Kl. k. Sächs. Ges. XXV–XXVIII, 1899–1903), but for all that, with proper qualifications, it remains substantially true.
[52] Quoted in Mr John Bishop’s interesting article in Todd’s Cyclopaedia, III, p. 443.
[53] There is probably also another factor involved here: for in bending, and therefore shortening, the leg we bring its centre of gravity nearer to the pivot, that is to say, to the joint, and so the muscle tends to move it the more quickly.