XXIV

Among Prerogative Instances I will put in the third place Striking Instances, of which I have made mention in the First Vintage Concerning Heat, and which I also call Shining Instances, or Instances Freed and Predominant. They are those which exhibit the nature in question naked and standing by itself, and also in its exaltation or highest degree of power; as being disenthralled and freed from all impediments, or at any rate by virtue of its strength dominant over, suppressing and coercing them. For since every body contains in itself many forms of natures united together in a concrete state, the result is that they severally crush, depress, break, and enthrall one another, and thus the individual forms are obscured. But certain subjects are found wherein the required nature appears more in its vigor than in others, either through the absence of impediments or the predominance of its own virtue. And instances of this kind strikingly display the form. At the same time in these instances also we must use caution, and check the hurry of the understanding. For whatever displays the form too conspicuously and seems to force it on the notice of the understanding should be held suspect, and recourse be had to a rigid and careful exclusion.

To take an example: let the nature inquired into be heat. A striking instance of the motion of expansion, which (as stated above) is the main element in the form of heat, is a calendar glass of air. For flame, though it manifestly exhibits expansion, still, as susceptible of momentary extinction, does not display the progress of expansion. Boiling water, too, on account of the easy transition of water to vapor or air, does not so well exhibit the expansion of water in its own body. Again, ignited iron and like bodies are so far from displaying the progress of expansion that in consequence of their spirit being crushed and broken by the coarse and compact particles which curb and subdue it, the expansion itself is not at all conspicuous to the senses. But a calendar glass strikingly displays expansion in air, at once conspicuous, progressive, permanent, and without transition.

To take another example: let the nature inquired into be weight. A striking instance of weight is quicksilver. For it far surpasses in weight all substances but gold, and gold itself is not much heavier. But quicksilver is a better instance for indicating the form of weight than gold, because gold is solid and consistent, characteristics which seem related to density; whereas quicksilver is liquid and teeming with spirit, and yet is heavier by many degrees than the diamond and other bodies that are esteemed the most solid. From which it is obvious that the form of heaviness or weight depends simply on quantity of matter and not on compactness of frame.