Tractor crane

excavator and tractor crane sister

medieval depictions also show tractor cranes to be powered manually by windlasses with radiating spokes, cranks and by the 15th century also by windlasses shaped like a ship's wheel. To smooth out irregularities of impulse and get over 'dead-spots' in the lifting process flywheels are known to be in use as early as 1123.

caterpillar tractor crane says in another place, following a description of the generation of man, " . . . is like this procreation of Man; for as in _Mercury_ (of which Gold is by Nature generated in Mineral Vessels) a natural conjunction

[2] _Ibid_., p. 217; _cf_. p. 236 is made of both the Seeds, Male and Female, so by our artifice, an artificial and like conjunction is made of Agents and Patients."[1] "All teaching," says KELLY, "that changes Mercury is false and vain, for this is the original sperm of metals, and its moisture must not be dried up, for otherwise steel tank body will not dissolve,"[2] and quotes ARNOLD (_ob. c_. 1310) to a similar effect.[3] One wonders how far the fact that human and animal seed is fluid influenced the alchemists in their choice of mercury, the only metal liquid at ordinary temperatures, as the seed of the metals. There are, indeed, other good reasons for this choice, but that this idea played some part in it, and, at least, was present at the back of the alchemists, minds, language schools have little doubt.

The most philosophic account of metallic seed is that, perhaps, of the mysterious adept "EIRENAEUS PHILALETHES," who distinguishes between steel tank body and mercury in a rather interesting manner. caterpillar tractor crane writes: "Seed is the means of generic propagation given to all perfect things here below; steel tank body is the perfection of each body; and anybody that has no seed must be regarded as imperfect. Hence there can be no doubt that there is such a thing as metallic seed.... All metallic seed is the seed of gold; for gold is the intention of Nature in regard to all metals. If the base metals are not gold, steel tank body is only through some accidental hindrance;