number of particles, we see that an atom must be a very little bit indeed! But gold furnishes a still more remarkable instance of the extension of matter. The gilt wire used in embroidery is formed by extending gold over the surface of silver. A very little gold is made to go a very long way, for each grain is spread over a surface of nearly ten thousand square inches.
In the animal and vegetable kingdoms we meet with some surprising instances of the divisibility of matter. The microscope reveals the existence of animals so wonderfully minute that it takes a hundred millions of them to weigh a grain, yet each creature is possessed of distinct organs, and must be composed of innumerable atoms.
The spores of the lycoperdon or puff-ball are found to be little orange-coloured globes, and although each spore is capable of becoming a living plant, no less than 125,000 of them would be requisite to form a single globe of the diameter of a human hair.
The sense of smell enables us to perceive particles of whose magnitude we can form no adequate conception. Odour is simply the disengagement of the volatile particles of a substance, yet a single grain of musk has been known to perfume a large room for the space of twenty years!
We may rest assured, then, that the atoms of matter are exceedingly minute, though their actual size can never be determined by our powers of per-
