particle of light were equal in size to the twelve hundred thousandth part of a small grain of sand,--supposing light to be material--we should be no more able to withstand its force than we should that of sand shot point blank from the mouth of a cannon. Every object would be battered and perforated by such celestial artillery, till our world were laid in ruins, and every living being destroyed. And herein are the wisdom and benevolence of the Creator displayed in making the particles of light so extremely small as to render them in some degree proportionate to the greatness of the force with which they are impelled; otherwise, all nature would have been thrown into ruin and confusion, and the great globes of the universe shattered to atoms. We have many proofs, besides the above, that the particles of light are next to infinitely small. We find that they penetrate with facility the hardest substances, such as crystal, glass, various kinds of precious stones, and even the diamond itself, though among the hardest of stones; for such bodies could not be transparent, unless light found an easy passage through their pores. When a candle is lighted in an elevated situation, in the space of a second or two, it will fill a cubical space (if there be no interruption) of two miles around it, in every direction, with luminous particles, before the least sensible part of its substance is lost by the candle:--that is, it will in a short instant, fill a sphere four miles in diameter, twelve and a half miles in circumference, and containing thirty-three and a half cubical miles with particles of light; for an eye placed in any part of this cubical space would perceive the light emitted by the candle. It has been calculated that the number of particles of light contained in such a space cannot be less than _four hundred septillions_--a number which is _six billions_ of times greater than the number of grains of sand which could be contained in the whole earth considered as a solid globe, and supposing each cubic inch of it to contain ten hundred thousand grains. Such is the inconceivable tenuity of that substance which emanates from all luminous bodies, and which gives beauty and splendour to the universe! This may also be evinced by the following experiment. Make a small pin-hole in a piece of black paper, and hold the paper upright facing a row of candles placed near each other, and at a little distance behind the black paper, place a piece of white pasteboard. On this pasteboard the rays which flow from all the candles through the small hole in the black paper, will form as many specks of light as there are candles, each speck being as clear and distinct as if there were only one speck from a single candle. This experiment shows that the streams of light from the different candles pass through the small hole without confusion, and consequently, that the particles of light are exceedingly small. For the same reason we can easily see