23: The Instances of Quantity

23. Instances of quantity or the doses of nature

⁴⁷ These measure the powers by the quantity of bodies, and point out the effect of the quantity in the degree of power.

Some powers only subsist in the universal quantity, or such as bears a relation to the confirmation and fabric of the universe.

Thus, the earth is fixed, its parts fall.

The waters in the sea flow and ebb, but not in the rivers, except by the admission of the sea.

Then, again, almost all particular powers act according to the greater or less quantity of the body. Large masses of water are not easily rendered foul, small are. New wine and beer become ripe and drinkable in small skins much more readily than in large casks.

If a herb be placed in a considerable quantity of liquid, infusion takes place rather than impregnation; if in less, the reverse.

A bath, therefore, and a light sprinkling, produce different effects on the human body. Light dew, again, never falls, but is dissipated and incorporated with the air; thus we see that in breathing on gems, the slight quantity of moisture, like a small cloud in the air, is immediately dissolved. Again, a piece of the same magnet does not attract so much iron as the whole magnet did.

There are some powers where the smallness of the quantity is of more avail; as in boring, a sharp point pierces more readily than a blunt one; the diamond, when pointed, makes an impression on glass, and the like.

We must not be contented with a vague result. We must inquire into the exact proportion of quantity requisite for a particular exertion of power.

One could suppose that:

• the power bears an exact proportion[244] to the quantity.
• if a leaden bullet of one ounce, for instance, would fall in a given time, one of two ounces should fall twice as rapidly, which is most erroneous.

Nor does the same ratio prevail in every kind of power, their difference being considerable.

The measure, therefore, must be determined by experiment, and not by probability or conjecture.

Lastly, we must in all our investigations of nature observe what quantity, or dose, of the body is requisite for a given effect, and must at the same time be guarded against estimating it at too much or too little.